In the help files it says:
How do I change my user name?
Unfortunately this is not possible. For consistency and to prevent confusion for other users, the registered name must remain as it was entered when you signed up. Subscribers can request that their name be modified to correct spelling and capitalisation.
so I guess this is not possible.
th
This isn't a common practice, but I do very occasionally change names at a user's request. I will only do so if that user contacts all of their opponents and informs them, or updates their profile to indicate the change.
If a user has used their personal name, and wishes to change it, then I will normally always make the change, subscriber or not.
-Russ