Good point on vindman.
I think the retiree thing applies to ready reserve. You?
It can be done somewhere in this mess:
42 U.S. Code ยง 212 - Retirement of commissioned officers
(c)Recall to active duty
A commissioned officer, retired for reasons other than for failure of promotion to the senior grade, may (1) if an officer of the Regular Corps entitled to retired pay under subsection (a) or under section 213a(a)(19) of this title, be involuntarily recalled to active duty during such times as the Commissioned Corps constitutes a branch of the land or naval forces of the United States, and (2) if an officer of either the Regular Corps or Ready Reserve Corps, be recalled to active duty at any time with his consent.
We had a mustang O-5 retire (30 years) when accused of conduct unbecoming an officer (an affair with an E-4s wife). The investigation revealed enough concern that sexual assault and rape charges were preferred. He was recalled to stand a general courts martial and was found guilty of conduct unbecoming only. He was demoted to O-3 then he retired at the lower grade.
I think with his 30 years in he was not in the ready reserve. It was messy all the way around and the Air Division commander wanted to nail him because of the negative public image it presented.