Is it permissible for a man to represent his wife for hatarat nedarim?

Usually, a person must stand before a beit din of three men and ask for an absolvement of his vows, known as hatarat nedarim. The Shulhan Arukh (234:56) rules that a husband may serve as a shaliach (agent) for his wife and to absolve her vows. The Taz (46) explains that he may do this based upon the principle of "ishto kegufo," which teaches that a man’s wife is like him for certain laws. It is, however, important that the husband informs the beit din that he is acting as her agent and that he specify her vow. The Ben Ish Hai (Rav Paalim 4:34) rules that only a husband can serve as his wife’s agent for hatarat nedarim.

The halacha also says that the husband should not gather a beit din, rather, he may only approach them to absolve the vows of his wife if they were already assembled..

Summary: A husband can represent his wife in front of a beit din and perform hatarat nedarim, as long as the beit din is aware that he is absolving her vows, and that he specify his vows to the beit din.