From: Rabbi Moshe Sofer
To: Unknown recipient
A man whose wife died on Chol HaMoed Pesach wished to remarry after twelve months but before three complete Regalim had passed. The Chasam Sofer agrees with Rabbi Akiva Eiger's permissive ruling, demonstrating through multiple converging leniencies — including counting Rosh Hashanah and Yom Kippur as Regalim under the mourning rationale, incorporating Purim, applying the Ritzvah's leniency based on the wife's publicly known illness, and invoking the risk of being preempted by another suitor — that the marriage may be permitted.
Source: Shu"t Chasam Sofer YD §350