In April, Linden Labs announced that premium members could pay to have their legacy user names changed. If you have given permissions in any Spot On product configuration notecard (such as Stage Manager or Costume Assistant), and that person has changed their user name, you will need to change the name in the notecard. Do not use display names!
Also, just as an FYI if you changed your name, don't be shocked when people on your friends list IM you to ask..........who are you?!