Cannon Fodder Awakens and Changes the Plot Development

Nanning Ci died, but she came back to life. When she was resurrected, she found that she and the people around her were cannon fodder in the novel. She was the female supporting character in the novel, her best friend was the vicious Bai Yueguang in the substitute novel, and her best friend's sister was the heroine in the sad novel. It seems that it is not difficult for her to change all the endings. Why is this?