#1 is OK in a formal context. #2 is awkward and unnatural.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Anonymous2.Thank you again for your agreeing [to do so and so].You don't want this one. The 'you' in "Thank you" already makes it clear that 'you' are agreeing. Adding it again is redundant. Obviously, I don't thank you for something that someone else did.