Harold Crick, the main character, has heard he is going to die soon, and spends much of the movie trying to avoid this "imminent death;" begging Karen Eiffel to change the ending of her book and keep him alive. But in talking with his literary adviser, Professor Hilbert, Harold is asked to willingly die for the sake of Eiffel's book, as can be seen here:
This scene raises some serious questions for us as viewers. What is the value of our own life? How much can we sacrifice for another person? What does it take for us to be willing to die for someone else?
In this scene, Harold says, "I can change . . . " and he does change, but not to avoid his death, but to accept it. How did this happen?
Harold started changing from the very beginning of the film when he heard Eiffel's narration. He didn't change drastically right away, but he became more aware of himself and the world around him, more conscious of what he was thinking and doing. He changed even more having to interact with Ana. She is so opposite of him, she's free-spirited, opinionated, colorful. Ana changes him a lot, especially in the day of the cookie scene. After spending all day enveloped in her world, he comes down to leave and she's just finished pulling cookies out of the oven.
Right after the video cuts off he realized she baked the cookies specifically for him, and that he was "screwing everything up" by not accepting them.
Throughout the day, Harold started to see Ana as a person, rather than just a auditee. He learned her story, and watched her life.
Hearing Eiffel's narration, and spending time around Ana, gave Harold something to focus on other than himself, which is the key to his willingness to die the way Eiffel originally wrote. Caring about someone else made him the type of person who would tell Eiffel to keep her story the way it was. Harold became willing to sacrifice his life for Eeffel's story, so she became willing to sacrifice her story for his life.