Complex sentence: Hahn was promoted to the rank of SS-Standartenfuher (colonel) and reassigned to the Western Front in December, 1944 he was stationed in the Rhenish town of Cochem and served as commander of "Einsatzgruppe L" during the Battle of the Bulge.
Split into simpler sentences: Hahn was promoted to the rank of SS-Standartenfuher (colonel) and reassigned to the Western Front in December, 1944. He was stationed in Cochem and served as commander of "Einsatzgruppe L" during the Battle of the Bulge.