I have recently been informed as to who my BGO is (He is a Lieutenant Commander) and I was planning on contacting him via email ASAP. However, I do not know how to address him when writing the email (I.E. "Dear so and so"). Should I address him at Lieutenant Commander so and so, Commander so and so, Dear Sir? I would like to sound professional and proper in my first personal contact with the academy. Any other suggestions are greatly appreciated.