Never tried this but here is the link to the FAQ about changing your username.
http://support.chess.com/Knowledgebase/Article/View/32/0/how-can-i-change-my-username
I think that may be fairly new, as I recall in the past you had to open a ticket and could only do it one time (or I could be remembering it incorrectly) ... just fully read that, you still can only change it once but looks like it is easier to do now.
Hello, i would lke to change my user name but everytime i try to edit it, it says i cant change while logged into live chess? How do i logout out of live chess? Ive logged out of the site, log back in get the same response. Sorry if this is a stupd question im not very computer literate.