Grete Samsa, Gregor's sister, most definitely goes through a "metamorphosis" as does every member of the family. Before Gregor's change, Grete is described as a "useless" daughter. She has taken violin lessons, but she isn't very good. She doesn't leave the house often. She is timid and seemingly afraid of the world. She "whispers" and "wimpers" at Gregor's door to get him to get up and come out to breakfast. The entire family depends on Gregor for their well-being and existence.
She is a good soul, however, as she is the one who takes care of Gregor when his secret is discovered. She is afraid of him in his new state, but she attempts to be caring and kind.
After Gregor's change, Grete also gets a job outside of the house. She is stepping into Gregor's role of caretaker of the family. However, because of her new duties, she also begins to neglect Gregor and her caretaking duties of him. Even so, she displays an uncharacteristic anger when their mother cleans Gregor's room while Grete is away from the house.
Although at the beginning of the story Grete seems to have the closest and most loving relationship with Gregor, she is the one who argues most vigorously for getting rid of him.
So, change is not always a good thing. In Grete, she has discovered independence, but she has become colder and less loving as a result. Oddly enough, her parents see her as growing into her womanhood and declare she is ready for a husband.