The two excerpts that show how Grete transformed in the story are:
Father. You've got to get rid of the idea that that's Gregor. We've only harmed ourselves by believing if for so long.
Grete was becoming livelier. With all the worry they had been having of late her cheeks had become pale, but, while they were talking, Mr. and Mrs. Samsa were struck almost simultaneously, with the thought of how their daughter was blossoming into a well built and beautiful young lady.
Step-by-step explanation:
Grete Samsa is the sister of Gregor (the main character) of the story in Metamorphosis by Franz Kafka. Having to face the transformation of his brother into a cockroach, Grete grows from being a shy girl to a strong young woman, in the first part of the story Grete has a weak personality and lets other mistreat her but as the story continues Grete's personality becomes stronger. Grete is the only member of Gregor's family that understands Gregor and can face him as a cockroach, and her new responsibilities are what make her confidence grow, she is the one that realizes that Gregor has to go, and her parents see her transform into an active and outgoing girl.