Complex sentence: Later that month, Lovato announced she would leave "Sonny with a Chance", in which she portrayed the main character Sonny Munroe, because she wanted to focus on her music career rather than acting.
Split into simpler sentences: Later that month, was announced that she would leave "Sonny with a Chance", in which she portrayed Sonny Munroe, the main character. Lovato left the show because she wanted to focus on her music career more than acting.