Complex sentence: After spending time as a patient in Brooke General Hospital, he reverted to retired status on 10 May 1946 but was later advanced to the grade of lieutenant general on the United States Air Force retired list by an Act of Congress on 29 June 1948.
Split into simpler sentences: After spending time as a patient in Brooke General Hospital, he reverted to retired status on 10 May 1946. Brett was advanced to the grade of lieutenant general on the United States Air Force retired list by an Act of Congress on 29 June 1948.