How to remove a user from radutmp?

We're using freeradius and allowing no simulataneous login (e.g. Simultaneous-Use := 1). Sometimes things get bolixed. Is there a way to remove a record from /var/log/radutmp? I notice that this seems to have a custom format (i.e. a struct radutmp which is not a Unix utmp or wtmp format). Failing

Solved! -- How to remove a user from radutmp?

Sorry - I just noticed the radzap program which seems to do the trick of removing a user from radutmp.. - List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html