Beis Shamai holds that if the father of an Arusah annuls her Neder and the Chasan subsequently dies prior to hearing of the Neder the father may annul the remaining portion of the Neder. (1)
Beis Hillel holds that the father may not annul the remaining portion of the Neder upon the death of the Chasan. (2)
A father or husband who affirms the Neder of his daughter or wife may be released from his affirmation by a Chacham.
It is not possible to be released from the annulment of a Neder.
If a father or husband repeats his affirmation of a Neder if he is released from the first affirmation, the second one takes effect.
If a father or husband says Kayam Lichi and Meifar Lichi and the affirmation shall not be effective unless the annulment is effective, the Neder is annulled.
If someone says that this animal shall be a Temuras Olah Temuras Shelamim it is a Temuras Olah according to Rebbi Meir.
Rebbi Yosi holds that if his intention was for both a Temuras Olah and a Temuras Shelamim it is both a Temuras Olah and Temuras Shelamim. (3)
If a father or husband says Kayam and Meifar Lichi at one time it is not effective. (5)
If a father or husband says Kayam Lichi today it is a Safek whether it is equivalent to saying that the Neder shall be annulled tomorrow.
A BIT MORE
1. Beis Shamai holds that when the father annuls his portion of the Neder the Neder is Meigaz Gayiz (split in half) and the father inherits the remaining half upon the death of the Chasan and he may subsequently annul the remaining portion of the Neder.
2. Beis Hillel holds that when the father annuls his portion of the Neder the Neder is Miklash Kalish (weakened) and since the Neder is weakened the remaining portion is not significant enough to inherit to the father.
3. It shall be sent out to pasture until it gets a Mum and then it shall be sold and the proceeds should be used for both an Olah and Shelamim.
4. Anything that does not work one after the other does not work at the same time.
THE DEATH OF THE CHASAN
If the father of an Arusah annuls her Neder and the Chasan subsequently dies prior to hearing of the Neder, Beis Hillel holds that the father may not annul the remaining portion of the Neder upon the death of the Chasan. The Tur says in the name of the Ramban that if the Chasan died on the day that the father annulled the Neder even according to Beis Hillel the father may annul the entire Neder. The Taz explains the reason. Since if the father had not yet annulled the Neder at the time of the death of the Chasan he would not have the right to annul the entire Neder, the fact that he already annulled the Neder should not take away that right.
A SHORT TERM KIYUM
If a father or husband says Kayam and Mufar Lichi at the same time or if he says Kayam u'Mufar Lichi b'Vas Achas it is neither an affirmation nor an annulment. (Shulchan Aruch YD 234:44)
Therefore he still could do with the Neder as he wishes; he can either affirm it or annul it. (Shach)