The easiest solution I know is click on a user. Get their profile up. Then paste the user's name that you want, into the URL bar to replace the old user name.

It's quick and simple, but there's no easy function built into the site as far as I know.

awww that's sweet tho... that u went to all that trouble to find her.

http://www.flirtbox.net/search.php

Here you can enter a username or partial username if the user has posted on the forum...e.g. *oby* or whatever...