I recently needed to change my iPhone name from "iPhone" to something else for tethering purposes (receiving device kept getting confused and tried to connect to another iphone with the same name). When I go to reset the device name it is greyed out. If I were to attempt to name it "beast" or "master" it would "grey out" the confirmation button and not let me proceed. If I delete character and go back, the deleted characters disappear. The only option I have for editing the name is deleting characters. Right now my iPhone7 is named "i".