From: Rabbi Moshe Sofer
To: Rabbi Moshe Segal
The community of Tzehlim had bound itself by a neder al da'as rabbim not to sell their communal meeting house. The Chasam Sofer rules the sale is permitted on two grounds: the vow was directed only at communal leaders acting unilaterally, not at the entire community acting by consensus, so the annulment required is merely Rabbinic; and even under Rabbeinu Tam's stringent view, annulment is valid here because the building's inadequacy defeats the very purpose for which the vow was made. He provides detailed practical instructions for obtaining formal hatara through a representative, written regret, and a beis din outside the city.
Source: Shu"t Chasam Sofer YD §220