Complex sentence: Upon being exchanged some time later he was sent to his home in Philadelphia, and upon his recovery returned to the field, and in February, 1863, was commissioned as lieutenant-colonel of the 13th Pennsylvania Cavalry.
Split into simpler sentences: Upon being exchanged some time later he was sent to his home in Philadelphia. When recovered, he returned to the field and, in February, 1863, was commissioned as lieutenant-colonel of the 13th Pennsylvania Cavalry.