Complex sentence: After the fight for Rome in June 1944, the force was withdrawn once again to prepare for Operation Dragoon and in August 1944, Walker succeeded Robert T. Frederick as the unit's second, and last, commanding officer.
Split into simpler sentences: After the fight for Rome in June 1944, the force was withdrawn again to prepare for Operation Dragoon. In August 1944, Walker succeeded Robert T. Frederick as the unit's second, and last, commanding officer.