From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer responds to a series of challenges regarding shelichos (agency) in milah and pidyon haben, clarifying that an agent must be personally obligated in the mitzvah, distinguishing shelichos for acquisition (kinyan) from shelichos for mitzvah fulfillment, and explaining the 'al' vs. 'lamed' blessing formulas. He also addresses the eligibility of a Kohen or Levi as agents for pidyon, the validity of circumcision by a woman or non-Jew, and related questions about sacrificial offerings.
Source: Shu"t Chasam Sofer YD §296