How do I change my username?

I guess আপনি either contact Fanpop's staff অথবা remove your account and then re-register under a different screen name.

Go to your পরিলেখ and etit it. go to the bottom of the page and there will be something that looks like what is in the pic. Click it and put your pass in it. Then আপনি will have to make a new account.