Haruto worries about his younger brother being better than him and wishes that he had a cute sister. Being charmed so that his trouble will fade, he turned into Sora’s younger sister…
He gradually becomes a sister who loves her older (actually younger) brother, inside and out...
https://www.dropbox.com/s/evjhozfgp4hrrsb/Role-Change%20to%20Sister.pdf?dl=0