Trump could still be replaced on the ballot in some states if he withdraws

In 2002, the New Jersey supreme court allowed Democrats to replace Torricelli with Lautenberg after Torricelli withdrew. I believe that was in early October or late September. And then in Minnesota, Democrats were required to replace Wellstone on the ballot after he died, and ballots were reprinted. So I don't think it would be too late if Trump dropped out even though the filing deadlines have passed. But most likely votes that have already been cast for Trump would not count for his replacement. Again, that would depend on the state.