There is no nickname-changing (on the same account). You're right that you can let that account lapse and start a new one with a new nick, though, if you want. Changing nicks is a messy, manual process that takes too long ... in order to be fair to everyone (because a lot of people would like to change their nicks) it is not done for anyone.
We get a request to switch a nickname about once a day. For security and smooth system operation, we have formed the following policy on member account names (nicknamess):
Please realize that there is no provision in the software to change nicknames. It is simply not possible to do.
Member names are static. What you pick when you signup is what you get forever.
Nicknames will not be retro changed except in rare circumstances or to alleviate conflicts with other similar nicks or trademarks.
If you sign up a new nickname, we will not transfer over old information from previous member accounts.
If you lose your password and email address, we will not hand out either regardless of the situation. You are responsible for keeping your information current should you lose your password and need to use the lost password procedure.
I own the trademark (in Oz anyway) so I guess I'm safe :) ... but that's also kind of my reason. In my naivete I signed up using this and I'm interested in being more discrete - not that I have anything to hide mind you.