ROLEPLAY CHARACTER NAME/USERNAME [URGENT]

I was wondering how to change the username of that member to a roleplay character. eg for xena. username is rated_x_superstar but for the roleplay i want them to be recognised as that character name, without having to continually change their username. I know it can be done as ive seen it on another forum.

I'm not totally sure but if you enable character sheets, you can put something that says Roleplay Name:_ _ _ _ _ _ _

And then put your character's name