It would be a NPC which you have to pay for, to change your hair.
I know there was (or there was going to be) and item on the cash shop to change your hair on the original game but, since that's not coming anytime soon...
Just got and idea, maybe when you create a character, in the character selection room there'd be like an option where you have some kind of "token" which you can use to re-create your character.
You only have one, but it's a nice thing if you want to change something, and if you want to change something again, you gotta pay. With cassshhh.