Change of real name is a “one time chanced proposed functionality” to be implemented in the future. We are aware that users might have made mistake while entering their real name at the point of registration and there’s a plan for that so as to claim your Pi balance.
While change of username is something that can only be done by the Core Team manually. For now, priority is given to user with inappropriate username to be changed with clean and pure one so that we can have a healthy and better community.
Hopefully, all users might have the one time chance in-app functionality to change their username. However, it is yet to be figured out. Let’s keep our fingers crossed and keep mining.