Complex sentence: After the War Korn would remain in the Naval Reserves, and in 1975, he was promoted to Rear Admiral in the Chaplains Corps, U.S. Naval Reserve, becoming the first Jewish chaplain to receive flag rank in any of the United States armed forces.
Split into simpler sentences: After the War Korn would remain in the Naval Reserves, and in 1975, he was promoted to Rear Admiral in the Chaplains Corps, U.S. Naval Reserve. With this promotion Korn became the first Jewish chaplain to receive flag rank in any of the United States armed forces.