Want to change your name anywhere, including while still in the dream-world? I have better and safer implemented the name-changing functionality into my Self-Cheat Guide mod, though note that mod contains other functionality (cheats).

Increases the name entry limit for Sunny from 6 characters to 15, and allows you to change Sunny's name through a book in the leftmost bedroom of Sunny's house during the day. Finally he is saved from being named "OMOCAT."

CAUTION: Don't save in Sunny's house and then remove the mod immediately after changing your name - go to another map and save there. Your save won't load in the vanilla game if it was made on a map with a modded event in it.