But authority can be used/imposed to take away some else’s authority, can’t it? Or can authority only be used to do something to someone, not to prevent someone from doing something?

If it was legal for certain people to slap certain other people, then the people doing the slapping would have the authority over the people being slapped to slap them. But then if the law was changed and took away their authority to slap them, that would be using authority over those slappers to stop them. Does this make sense? Both can be true at the same time

Just as it imposed authority over them to take away their authority, right?

Removing a kind of authority of the people over other people, but wouldn’t it be imposing an authority from the government upon the remaining slave owners?