From: Rabbi Moshe Sofer
To: Rabbi Moshe
A Jew forgot to sell a barrel of whiskey before Pesach, and it remained in a distant rented courtyard beyond his reach. The Chasam Sofer rules that after Pesach the owner should affirm the non-Jew's possession and request a different barrel or monetary equivalent as a gift.
Source: Shu"t Chasam Sofer OC §112