I believe there is a tiny-small-itsy-bitsy chance they might change your username, but there should be a very VERY good reason for it. Try emailing Ferret (ferret@armorgames.com) and explain your situation to him. =)
But DO make sure you have a good reason for your request, because a simple "I don't like it" or a "I got bored with it" doesn't go here, ok?