The case of a man who discovers later that he didn't have all the details at the time he revoked a vow. With a parallel to tearing keriyah in mourning, and introducing how long it takes to revise the information of the situation. Plus, a mishnah about a woman who swears off figs and grapes, and that vow is revoked apparently partially - is that sufficient? Plus a second mishnah on one who doesn't know he has the right to revoke a vow, and later discovers it - does he get an extension of time to do so? What if he knows he can revoke vows, but doesn't know that what he'd just heard was a vow?