Regarding being a member, or a pastor if you do not believe in Ellen White:
The answer is a bit complicated. The short answer is that it is possible to be a member of the church and not accept Ellen White. But it largely depends on the local church and minister.
The longer answer:
The Seventh-day Adventist church publishes the Seventh-day Adventist Church manual and includes what are meant to be procedures for the churches. Included in this are two variations of Baptismal vows, a traditional and an alternate. Both include acceptance of the fundamental beliefs of the SDA church. Not every church will use these, but many still will.
You can see the vows in their entirety on page 51:
The baptismal vows do not mention Ellen White. So that would sound like you don't need to accept her. However, they do indicate acceptance of the fundamental beliefs.
11. Do you know and understand the fundamental Bible principles as
taught by the Seventh-day Adventist Church? Do you purpose, by the grace
of God, to fulfill His will by ordering your life in harmony with these
principles?
2. Do you accept the teachings of the Bible as expressed in the
Statement of Fundamental Beliefs of the Seventh-day Adventist Church, and
do you pledge by God’s grace to live your life in harmony with these
teachings?
The Seventh-day Adventist Fundamental beliefs include Ellen White:
18 The Gift of Prophecy
The Scriptures testify that one of the gifts of the Holy Spirit is prophecy. This gift is an identifying mark of the remnant church and we believe it was manifested in the ministry of Ellen G. White. Her writings speak with prophetic authority and provide comfort, guidance, instruction, and correction to the church. They also make clear that the Bible is the standard by which all teaching and experience must be tested. (Num. 12:6; 2 Chron. 20:20; Amos 3:7; Joel 2:28, 29; Acts 2:14-21; 2 Tim. 3:16, 17; Heb. 1:1-3; Rev. 12:17; 19:10; 22:8, 9.)
So in many churches acceptance of Ellen White is required to become a member. However, some churches do not practice this. And some dispense with the vows and the process outlined in the manual.
Ellen White for her part did not feel that acceptance of the visions should be a test of fellowship for those who were otherwise sincere, and had little knowledge of the visions, and who did not resist them actively:
From Testimonies for the Church Volume 1:
In the last vision given at Battle Creek I was shown that an unwise course was taken at ----- in regard to the visions at the time of the organization of the church there. There were some in ----- who were God’s children, and yet doubted the visions. Others had no opposition, yet dared not take a decided stand in regard to them. Some were skeptical, and they had sufficient cause to make them so. The false visions and fanatical exercises, and the wretched fruits following, had an influence upon the cause in Wisconsin to make minds jealous of everything bearing the name of visions. All these things should have been taken into consideration, and wisdom exercised. There should be no trial or labor with those who have never seen the individual having visions, and who have had no personal knowledge of the influence of the visions. Such should not be deprived of the benefits and privileges of the church, if their Christian course is otherwise correct, and they have formed a good Christian character.
Some, I was shown, could receive the published visions, judging of the tree by its fruits. Others are like doubting Thomas; they cannot believe the published Testimonies, nor receive evidence through the
testimony of others; but must see and have the evidence for themselves. Such must not be set aside, but long patience and brotherly love should be exercised toward them until they find their position and become established for or against. If they fight against the visions, of which they have no knowledge; if they carry their opposition so far as to oppose that in which they have had no experience, and feel annoyed when those who believe that the visions are of God speak of them in meeting, and comfort themselves with the instruction given through vision, the church may know that they are not right. God’s people should not cringe and yield, and give up their liberty to such disaffected ones. God has placed the gifts in the church that the church may be benefited by them; and when professed believers in the truth oppose these gifts, and fight against the visions, souls are in danger through their influence, and it is time then to labor with them, that the weak may not be led astray by their
influence. It has been very hard for the servants of God to labor in -----, for there has been a class of self-righteous, talkative, unruly ones there, who have stood in the way of the work of God. If received into the church, they would tear it to pieces. They would not be subject to the body, and would never be satisfied unless the reins of church government were in their own hands. Brother G sought to move with great caution. He knew that the class who opposed the visions were wrong, that they were not genuine believers in the truth; and therefore, to shake off these clogs, he proposed to receive none into the church who did not believe the third angel’s message and the visions. This kept out some few precious souls who had not fought against the visions. They dared not unite with the church, fearing that they should commit themselves upon that which they did not understand and fully believe.
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m.egwwritings.org
Here is a discussion of the issue on the Ellen White Estate web site:
Question 26: Is the inspiration of Ellen White a test of fellowship? (“Ellen G. White a Test for Membership?”)
Question:
When Walter Martin met with leaders of the Adventist Church, he asked whether belief in Ellen G. White’s writings was a test of fellowship. Instead of answering his question, the leaders quoted Ellen White herself Speaking about those who did not fully understand the gift, she said, “Such should not be de-prived of the benefits and privileges of the church” (see Testimonies for the Church, 1:328).
Why then is belief in the role of Ellen White included as one of the fundamental beliefs of the Seventh-day Adventist Church? I have asked more than a hundred Adventist ministers if they would baptize and accept into the fellowship of the church a person who didn’t believe in the role the church claims for Mrs. White. To this date, I have yet to have one tell me that he or she would do so. Ellen White says that those who do not understand the gift should not be denied the benefits and privileges of the church. Why then did the General Conference president, in an article titled “The Church—Authority and Responsibility” (Adventist Review, May 1995), write, “I cannot say that I don’t accept this... fundamental belief of the church and still claim to be part of the church ”?
Answer:
I don’t have a definitive answer to your question about the fundamental beliefs. As far as I know, this was the first statement of our fundamental beliefs ever to name Mrs. White and to express explicitly that the gift of prophecy was manifested in her ministry. I believe I heard that there was discussion about the advisability of including this point. I don’t know what the arguments were that finally prevailed. Of course, I can speculate. It may be that there was broad recognition that, in fact, this article of the fundamental beliefs does indeed describe what the vast majority of Adventists believe, and it would be only honest to come out and say it. For many decades—perhaps throughout the history of this church as an organized movement—we have held that people considering church membership should be taught about the role of the gift of prophecy among us. We haven’t required that people affirm their belief in Ellen White prior to baptism, but our general understanding has been that we ought not to baptize someone who is opposed to accepting her prophetic ministry. This would be unfair to the new member, who would certainly be like a fish out of water. And it would be unfair to the church, which would have a note of discord established within it. On the other hand, let me be the first Adventist minister to answer your question about baptism affirmatively—with this qualification. In the passage from which you have quoted, Mrs. White indicates the conditions: first, the potential members do not yet understand the gift (they haven’t had enough information to make an intelligent choice), and second, “if their Christian course is otherwise correct, and they have formed a good Christian character.” (These words follow right on the ones you quoted.) Such individuals are in the category Mrs. White spelled out in the paragraph just before the one you quoted, “Others had no opposition [to the visions], yet dared not take a decided stand in regard to them.” This, I take it, was from lack of information about the visions or experience with them. They simply didn’t know, but they were not opposed. I wouldn’t hesitate to baptize such a person. The baptismal vow in the Seventh-day Adventist Church Manual poses the right question: “Do you accept the biblical teaching of spiritual gifts and believe that the gift of prophecy is one of the identifying marks of the remnant church?” If people accept that, then they may join the church if they wish to do so while they examine for themselves the evidences that Mrs. White’s ministry was a genuine manifestation of this gift that they believe in and the presence of which they believe to be an identifying mark of the remnant church of the last days. Lastly, you asked about the General Conference president’s statement that people can’t say they don’t accept this fundamental belief and still claim to be part of the church. Expressing disbelief would be opposition, wouldn’t it? Here we have moved out of the realm of uncertainty, of needing additional time to study and to gain evidence. To say, “I don’t accept this” is to reject it, isn’t it? It is not the same as the group Mrs. White was speaking of, who “had no opposition [to the visions], yet dared not take a decided stand in regard to them.” Regarding the person who refuses to accept after being a member and having time and opportunity to examine the validity of the gift, I would stand with the General Conference president and say that people cannot reject one of the fundamental beliefs of the church and still claim to be a part of the church. “Can two walk together, unless they be agreed?” (Amos 3:3). Such people would be uncomfortable in the church, and the church would be troubled by their influence. If people believe the members of this church are so deceived as to follow one who claimed to have the prophetic gift but who did not have it, why would they want to join them?
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Nor is this a new issue:
1964 Francis Nichols
Why I Believe in Mrs. E. G. White
There is another question that is sometimes asked: Should a person be taken into the church who does not accept Mrs. White as God’s special messenger to the remnant church? We believe that the Adventist ministry in general would quickly answer, No. How could we answer otherwise? In view of the fact that such a belief in Mrs. White is one of our articles of faith, why would anyone wish to belong to our church if he did not accept Mrs. White? Would it be fair to him to bring him into the church unless, first, he well understood the doctrine of spiritual gifts, and second, was ready to accept that doctrine? Would we not be doing both him and the church a distinct disservice? Would we not be running the grave risk of later tension and discord?
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In regards to removing people from fellowship who do not accept Ellen White, this is not often done in practice that I have seen. However, the church manual does indicate valid reasons for discipline, and the first one is denial of faith in the gospel and in the fundamental beliefs. Again, Ellen White is part of the fundamentals.
The reasons for which members shall be subject to discipline are:
1. Denial of faith in the fundamentals of the gospel and in the Fundamental Beliefs of the Church or teaching doctrines contrary to the same.
In regards to whether a person may serve as a minister without believing in Ellen White's visions, ministers are usually not ordained if they do not believe in Ellen White's writings.
In regards to removing ordination credentials one of the more famous examples is Desmond Ford, a professor and scholar who raised questions regarding a key doctrine, and Ellen White. This is from the Ministry Magazine Glacier view documents. Glacier View was the venue for the Sanctuary review committee that heard Ford's views. The article below recounts the discussion between Ford and the leadership. Wilson was the General Conference president.
From the article "Events Since Glacier View"
The discussion turned to the matter of Ellen G. White and her role in doctrinal and theological matters. Her authority, in relation to Scripture, and the question of whether she could be considered a reliable, inspired commentary of Scripture was examined. In this area Dr. Ford set forth his viewpoint, and indicated that he cannot agree with what the church holds in this matter. Both Pastors Wilson and Bock pleaded with him to look again at the issues, but he indicated that to change his views without evidence would be to deny his conscience. He expressed a willingness to keep silent on these things, but said that it would be impossible for him to preach or support the commonly held Adventist positions without compromising his integrity. Pastor Wilson told him that a minister can not be silent on two such distinctive matters of doctrine and still represent the Seventh-day Adventist Church.
