Complex sentence: Buck and his co-director, Jennifer Lee, were ultimately able to solve the dilemma by depicting Elsa and Anna as sisters; this led to Elsa being rewritten as a sympathetic, misunderstood character.
Split into simpler sentences: Buck and his co-director, Jennifer Lee, were ultimately able to solve the dilemma by depicting Elsa and Anna as sisters. This led to Elsa being gradually rewritten as a sympathetic, misunderstood character.