The father and the Chasan of a Na'arah ha'Me'orasah together may annul her Neder.
If the father annuls the Neder without the Chasan or vice versa it is not a valid annulment.
If either the father or Chasan annuls the Neder and the other one affirms the Neder the Neder no longer may be annulled. (1)
A husband may not annul Nedarim that were made prior to the Kidushin.
A husband may annul the Nedarim of his wife.
A husband may not annul Nedarim that his wife made prior to the marriage.
A father may annul the Nedarim of his daughter. (2)
An Arus may annul together with the father the Nedarim that his Arusah made prior to the Erusin.
A BIT MORE
1. However if the one who affirmed the Neder is released from his affirmation by a Chacham and the one who annulled the Neder annuls it again together with his partner according to some Rishonim it is valid.
2. If she is a Ketanah or a Na'arah and she is not yet an Arusah the father has the sole Zechus to annul her Nedarim.
AFFIRMATION PRIOR TO ANNULMENT
If either the father or Chasan annuls the Neder and the other one affirms the Neder the Neder no longer may be annulled. However if one of them affirms the Neder and is released from his affirmation prior to the annulment of the other, the Neder may be annulled. However if he is only released from his Neder after his partner annuls the Neder the Neder may no longer be annulled. (Netziv)
ANNULMENT OF THE
12TH CYCLE DEDICATION
NEDARIM OF AN ARUSAH
The Arus may not annul the Nedarim of his Arusah alone even if he is obligated to give her Mezonos nor may the father annul her Nedarim alone. They may annul her Nedarim in partnership even those Nedarim that she made prior to the Erusin. (Shulchan Aruch YD 234:5)
However a husband may not annul the Nedarim that his wife made prior to the marriage. (Taz)