You would have to PM Badspot to do so.
Be aware that he may decide that he doesn't want to, or can't do so immediately. He may also decide not to if he thinks your new name is really stupid, which he may or may not alert you about.
Anyways, if you send him a polite PM asking for a name change to PsychoLeet, he should get around to it, but if he doesn't, it may be because he doesn't want to, or that your message got bogged down in other messages that he recieves. You may not be his number one priority. Just send him another polite message sometime later. A name change isn't your main thing to worry about on the forums. (Not that there's really anything you should worry about on these forums).
Anyways, good luck with the name change.