Shavua Tov. Related to the subject of התרת נדרים, the release from vows, there is a necessary statement from the one attempting to be released from his vow.
This statement is also applicable in other areas of Jewish law. It is necessary to make the following declaration: “Had I known what the results of the vow were, I never would have made the vow.”
This can apply in a monetary case as well. If one released a contractor of his duties, but later found further damages, he can reopen the case. He can also claim that had he known about these damages, he never would have released the Kablan.
And a further case could apply in the case of a marriage annulment. A similar claim can be made by one of the parties in a marriage. Had I known that my new spouse had certain concealed medical issues, I never would have married him or her, is also a valid claim.
All of this is learned from the case of the annulment of vows.