10 U.S.C. § 12214: Officers; Air Force Reserve: transfer from Air National Guard of the United States

(a) Under such regulations as the Secretary of the Air Force may prescribe, and with the consent of the governor or other appropriate authority of the State concerned, an officer of the Air National Guard of the United States may be transferred in grade to the Air Force Reserve. (b) Unless discharged from his appointment as a Reserve, an officer of the Air National Guard of the United States whose Federal recognition as a member of the Air National Guard is withdrawn becomes a member of the Air Force Reserve. An officer who so becomes a member of the Air Force Reserve ceases to be a member of the Air National Guard of the United States.