Every Main Character represents one special character element. This element is either the cause of the story’s problem, or its solution. The Main Character cannot be sure which it represents since it is too close to home. Near the climax of the story, the Main Character must make a Leap of Faith and decide if it should stick with its approach in the belief that it is the solution, or jump to the opposite trait in the belief it has been wrong. When a Main Character decides to abandon its story-long approach for its counterpart, it is said to Change. And as a Changing Main Character, it will contain the crucial element/characteristic in the story.

Excerpted from
Dramatica Pro Story Development Software