Complex sentence: However, Jeannie has found Rooney's wallet on the kitchen floor and, with a change of heart, lets Ferris in and blackmails Rooney with the proof that he was the intruder, leaving Rooney to be attacked by the dog once again.
Split into simpler sentences: However, Jeannie has found Rooney's wallet on the kitchen floor, and with a change of heart, lets Ferris in. She then blackmails Rooney with the proof that he was the intruder, leaving Rooney to be attacked by the dog once again.