I have changed mine every now and then, we went through a phase earlier in the year when everyone changed to there real names and it got confusing ( for me anyway ).
I had trouble changing my name back to garyj, and have changed it temporarily for a lark and it is sometimes a pain to change back.
If you are having trouble to follow Jims steps again tomorrow??, sometimes it works, sometimes it doesn't!.
( I think Kev Loomes was one of the ones that changed, cannot remember who he was before! )