Can i remove/change Registration IP of super admin .
Why would you do this?
You would run a query in phpMyAdmin to update the "regip" and the "longregip" fields.
UPDATE mybb_users SET 'regip' = 'IP' WHERE 'uid' = 'UID'
http://community.mybb.com/thread-4720.html
You will need to change IP to the ip you want to set it to, and UID to the UID of the super mod.
I'm not sure about the longregip but a query would be needed for that as well.
Your welcome. I'm not sure if you need to update the longregip as well.