Date: 11 Kislev 5592
From: Rabbi Moshe Sofer
To: Rabbi Simcha Noson Ellenberg
The Chasam Sofer rules that beis din may permit a yavam to marry his fiancée despite an outstanding chalitzah obligation when the yevamah refuses to submit to Jewish court jurisdiction, as beis din has authority to suspend the Cherem of Rabbeinu Gershom as a sanction against a recalcitrant party. The permission is conditioned on the yavam providing guarantees that he will comply with whatever beis din decides once the yevamah agrees to appear.
Source: Shu"t Chasam Sofer EH I §1