Complex sentence: The 13th Psychological Operations Battalion (originally, the 13th Psychological Warfare Battalion (Enemy Prisoner of War)) is a Battalion in the United States Army Reserve.
Split into simpler sentences: The 13th Psychological Operations Battalion (originally, the 13th Psychological Warfare Battalion (Enemy Prisoner of War)) was a unit of the United States Army. It now functions as the 13th Psychological Operations Battalion in the United States Army Reserve.