I wouldn't worry about it though. I think that pretty much most of fanpop would prefer a different نام کا صارف to the one they have now. I don't know that for a fact obviously, but I've come across a lot of peeople who want to change their username.
It's why so many people make new accounts, but I don't advise that آپ do that. Because you'll only lose everything you've done and have to start over. And tbh, no one's that bothered about your username.
No آپ can't change it. The only way to make a new نام کا صارف is to make another Fanpop account. Now آپ can خارج the one that آپ have, but that's something that آپ probably don't wanna do. If I were آپ I would.