11-06-2012 12:00 AM
You would just need to do a security wipe of the device. This would remove any settings and information that is belonging to yourself.
As for the PIN once it's wipped if someone has your pin and tries to send a message they will get a message indicating that they are no longer assoicated and would like to send a friend request. At this time the new person and either accept or decline if they know the person.