I don't dare to do as in the title.
So I set root password first with
sudo passwd root, and then I change all other users to be standard user, none administrator, so no user can
If I want to set a administrator, just
su root with the password just set.
But now I wonder what happens if I didn't set root password in the beggining and then change all users to be standard user. Does it mean then this OS cannot be configured by sudoers forever? Is there any method to set new administrator?