There are a couple of workarounds you could try, though they are not ideal:
1. Restart the game: You could try restarting the game and giving your dog a different name when you start a new "pack" or family. This will technically give your dog a new name, but you will lose all your progress with that dog.
2. Edit the save file: This is a more advanced technique and could potentially corrupt your save file. You could try using a text editor to edit the save file and manually change the name, but this is not recommended for most users.
It's best to simply choose a name you like when you first start the game and stick with it.
Let me know if you have any other questions about Petz Dog Pack!