Changing Mysql values in an auto_increment field
 

I'm working on a script to change the userid in vBulletin because I need the admin's userid to be one for another script I'm working on.

I ran into the problem that the user table has the userid column as auto_increment and I've been told you should not UPDATE an auto_increment field.

All I need to do is change userid=1 to userid=3 and vice versa. Is there a 'good' way to do this or will UPDATE work just fine?

THANK YOU!