My mind wanders into unexpected places sometimes and makes the oddest connections. Yesterday as I walked in the wood, I found myself observing the first changing leaves of autumn. The changing leaf colors brought me back to my writing (in a round about sort of way).
Change is what we must create in our characters. If our protagonist stayed the same throughout our story, it would be pretty boring, wouldn’t it? So you have to make them become something they’re not by the end of your story.
Like the changing leaves, your character changes are often so subtle that you barely notice. For a while, she may stay the same, or she may fight the changes. But situations will eventually ensure the changes happen, just like the changing weather in September and October force the leaves to change.
Just as the leaves inevitably change in autumn, so must your protagonist.
Sometimes the changes appear to occur overnight. As a leaf drops from a tree, so too your character might drop some of his traits. As new leaves develop in the spring, so too may your character acquire new traits.
For example, you might have a weak woman, always taken advantage of by men, become a strong woman who finds a secure partner who brings out her strengths. You might have an extroverted, type-A guy suffer a terrible tragedy. He winds up giving up the bustling city, corporate life to live a life of solitude in the mountains where he can find his true spirit.
Now, in order for your character to go through this metamorphosis, something must happen. You have to have a trigger event, followed by situations that require certain reactions from your character. The reactions, in turn, help them to grow or change in the way you expect them to.
FYI, this change is called character arc.