One approach would be to move all the files over, but this seems like it would be tedious (correct me if there’s an easy way to do it within DreamHost’s system).
My preferred method is to adjust the DNS so that content doesn’t move anywhere and the domains just start pointing to the right places. I’ve done a bit of searching but have not come up with a process for doing this, and the DreamHost control panel doesn’t make it obvious that I can do it there.
Any ideas? Thanks!