IIRC, this question was asked by someone about a year ago. The only way for someone to change their name is to get one of the admins to do it. The problem with that is that if it's done for one person, it would have to be done for anyone and since there are approx 40,000 users, you would probably need another member of staff just to deal with all the requests.
IMO, the easiest way would be to just create another user.