How to removeownership

How do I remove somebody that has ownership on my server?
Using assmod

http://www.facepunch.com/image.php?u=197753&dateline=1271474180

http://www.facepunch.com/image.php?u=197753&dateline=1271474180

http://www.facepunch.com/image.php?u=197753&dateline=1271474180

And I was like baby baby baby, oh!

[editline]2:25[/editline]
Just find the ‘users.txt’ file for AssMod, and remove the person out of it.