It would be very difficult for him to get used to the new name, so be ready to get ignored! lol, I would start out with using it as sort of a "nickname" when you're playing/cuddling. next, begin calling him occasionally by that name, but have some sort of treat or toy to help get his attention, and make sure to praise him by using his new name every time he does something right(like answer to it! lol)
Lastly, be prepared for the fact that he may reject the new moniker (after all, he's had almost as many names as years on Earth....and he may like Toto, secretly calling you Dorothy in Pugglese)
My animals have always had nicknames that they answer too, aswell as their "real"name (rotty named Odin answers to Bud, Tubby, Stinker, Oldman, etc; and my Ferrets Ruby & Maximus are used to being called Ruby Tuesday, Princess, Schtinkeepoops, and Baby Boi)