I believe that is a pipe dream. Those who voted and got him in the first time have only been galvanised. Trump only stands to gain support. His based is entrenched with fortifications, and will not budge.
Respectfully, I cannot imagine a single person who is not already in the Trump camp switching over. I do realize that some people only watch media sources which, when confronted with daily scandals, scour the airwaves so they can feature on a justice of the peace in Podunk, USA who accepted a bribe. I sometimes watch Fox News just to see, when the biggest stories break, how many times they can dust off Hillary's emails and pretend (ho-hum) that they were EVER significant.
But don't you think that the anti-Trump camp is galvanized, too? They didn't come out in force in 2016, partly because they weren't inspired by Hillary, and partially because they thought that their friends and neighbors would see through Trump's lies, narcissism, greed, ignorance, sloth, and cheating and vote for Hillary--or stay home.
I remember sitting at the organ in church before the 2016 election, and hearing two parishioners in the front row bemoaning that they would be "required" to vote for Trump because he was "pro-life." I felt like shaking them and saying, "No, you are not required. If your gut tells you that he is completely untrustworthy and unqualified, you have to either stay home, ask for a write-in ballot, or vote for Hillary or a minor party candidate." How could anyone trust that Trump stood for anything--but making money for his company while in office?