From: Rabbi Akiva Eiger
To: Unknown recipient
Rabbi Akiva Eiger analyzes whether a husband's confirmation or annulment of his wife's vow can be performed through an agent or conditionally, concluding that the Tur's ruling against annulment without hearing creates interrelated doubts. He derives a novel ruling that if a husband first annuls conditionally and then unconditionally through an agent, the annulment takes effect under either possibility. The teshuvah closes with an unresolved discussion of whether conditions apply to purely verbal acts that cannot be delegated to an agent.
Source: Shu"t Rabbi Akiva Eiger §48