You would address a retired Rear Admiral as "Rear Admiral (Retired) [Full Name]" on the envelope and in the salutation of the letter.
How to address an envelope to a Retired Army Col and his wife.
Captain and Mrs.....
Use the military rank.
Councilman or Councilwoman Smith.
The Rt. Revd. Bishop A.B. Smith
When you have something to say about the policies in your area, then one person you might consider contacting is your councilman. Your city council is in charge of governing your area, as well as setting up rules and laws and making decisions about what is best for your city. If your councilman does not seem to be making decisions in your best interest -- or if you would like to point out an issue of importance that your councilman should be focusing on -- a letter is the perfect format.
You can address the envelope to a retired judge by using their full name followed by "Retired Judge" on the line below, and then their mailing address. For example: "John Doe Retired Judge 123 Main Street Anytown, USA."
The title "Captain", or the abbreviation CAPT would be appropriate. The salutation in a letter might read "Dear Sir" or "Dear CAPT Smith". When a politician or military officer retires, he's allowed to use the form of address of the highest rank held.
You can address the letter with "Judge [Last Name]" followed by their new professional title at the law firm. For example: "Judge Smith, Esq." Be sure to include their firm's name and address in the letterhead as well.
Undersheriff sir
Jim (Jane) Colonel Sir (Ma'am) or Mr/Mrs. Jim/Jane Doe, Col, USAF Retired