Complex sentence: The company is now a full-fledged company produced by the Kennedy Center, and it made its debut in the fall of 1999 during the Kennedy Center's "Balanchine Celebration", performing "Divertimento No.15".
Split into simpler sentences: The company is now a full-fledged company produced by the Kennedy Center. It made its debut in the fall of 1999 during the Kennedy Center's "Balanchine Celebration", performing "Divertimento No.15".