Hafarat Nedarim

Prior to Kiddushin

1. The Torah gives license to a man to revoke the Nedarim of his young daughter and those of his wife. This action is known as "Hafarah." A father can only revoke his daughter's Nedarim while she is a Ketana (below the age of twelve) or Na'arah (between twelve with Simanim and twelve and a half). Once she becomes a Bogeret (twelve and a half with Simanim) or reaches Nissuin, he may no longer revoke her Nedarim.

After Nissuin

1. The husband can revoke her Nedarim exclusively from Nissuin and on. Even if his wife is shrieking in disapproval, she cannot prevent her husband from revoking her Nedarim.
2. If they get divorced, the husband cannot revoke her Nedarim from the moment the divorce has taken effect and the Get has arrived in her hands. Thus, if the status of the divorce is unclear, he should not revoke any of her Nedarim. Similarly, if the divorce was made on condition or if the Get was handed to her courier (Shliach leHolacha) Post-facto, it would not be a valid Hafarah, unless it was a Get on conditio and the condition was not fulfilled.
3. If she heard that her husband passed away, remarried, and then found out that he's still alive, neither husband can revoke her Nedarim. The same is true regarding any marriage that violates a Karet level prohibition.

Types of Nedarim

1. The husband and father can only revoke Nedarim that are self afflicting to the woman or strain the bond between him and her. A Chacham, however, can annul any Neder.
2. Even if it was a Nedar Al Da'at Rabbim, the father and husband can still revoke it.
3. These Halachot apply equally to Shevuot, as well.