It is quite possible to change your avatar, as I just did. I clicked on "Change My Avatar" on the "My Account" page, selected a new avatar, and voila! I am no longer Dr. Lucky.
Or were you referring to the name? I don't know any way to change that without adding a totally transparent alias.
The General's parents are over for cake, so I'm hiding now. They're good people and all, but I'd rather have some me time, then sit and gossip about small town s##~. :-)