Date: 7 Tishrei 5578
From: Rabbi Moshe Sofer
To: Rabbi Aharon Suditz
A student vowed al da'as rabbim not to serve as ba'al tefillah in Sighet, adding an emphatic statement against any annulment. The Chasam Sofer rules the vow may be annulled because it was expressed in shevuah language (rabbinic force only), and because preventing the closure of a small synagogue constitutes a public mitzvah permitting annulment even of a neder al da'as rabbim. The annulment panel must be composed of outsiders, as all local residents have a vested interest, and a single annulment suffices though a double one is commendable.
Source: Shu"t Chasam Sofer YD §221