Your ingame name? If so just do /name
If your asking how to do it on the forums you just click on the top right where your name is, go to account settings, then display name & change it there.
Ping kdawg between 9 and 24 times in the discord and tell him that if he doesn't change it for you you're gonna assemble every titsRP hater to chargeback at the same time, effectively bankrupting titsRP.