Is it permissible for the woman's guardian to revoke an oral authorization before the marriage contract? And is a contract concluded without the guardian's consent considered a فضولي (unauthorized) marriage that becomes valid with his subsequent approval?

The woman has the right to revoke the agency of another to marry off her ward whenever she wishes before the contract; this is because agency is a revocable contract. Therefore, if the agent marries off the ward after being dismissed and knowing about it, his action is like the action of an unauthorized intervener (فضولي). The marriage arranged by an unauthorized intervener is a matter of dispute among scholars: some invalidate it, some make it contingent on the guardian's approval, and some differentiate between various situations concerning the guardian and the woman being married.