how do i change my retainers name?

[Shofie]

Does that not only change the appearance, not name?

Not entirely understanding what you're asking here, but you also use Retainer Fantasias to change the name. After you get out of the appearance editing menu, you get the option to rename them.

You can talk to a Retainer Advocate in any of the major cities, and they might have just an option to change the name without the Fantasia, but I'm at work and unable to check the game right now to confirm.

Either way, if you do use a Retainer Fantasia, you will need to talk to a Retainer Advocate to edit the character in any way.