Instead of an item that lets you change the flight of an existing dragon, it would be a lot less disruptive to let you temporarily change the element of one of your nests. I agree that people shouldn't be pushed to an unsupported behavior such as lending out their dragons, with the potential for scams and inconvenience to everybody, as the only possible avenue for getting hatchlings with a different eye color. (I get the initial intent was probably a purist 'users in Fire flight will only ever have fiery-themed pairs/fandragons/etc' mindset, but that's not how people work and nest renting is such an obvious loophole that clans 'using' nests of other elements is going to happen anyway.