If you or your client makes a mistake, you cannot revert it, there aren’t any backups being made
GHL should he creating backups of each subaccount automatically, so that if someone needs to revert to a previous version, they can
Right now, if you make a mistake and lose everything in opportunities or contact creation dates, you lose it all and there is no way to get it back (based on what support told me), which is completely ridiculous in my opinion