Re-releasing under a different title

I got my rights back from my publisher and want to re-release one of my books under a different title. Does anyone know if you can/should/have to connect it to the old version as a different edition, or is it completely its own? And if it is a considered a completely separate work, is there a way to take the old one down so that readers aren’t like umm this is the same book what’s going on here?