Why can't I change access rights on reports that are already created? Especially as an administrator?

This only works for the reports showed in the reports panel, but it does not restrict access to this reports if those are already in a page the user have access.

I do not know how to deny  access to report base in user roles once they are already placed in accessible pages.

I do not know how to modify the access option in the reports from common to not common.