Magic Forums

So I am not actually a practicing wiccan nor do I practice an extent of the religion or any magic or magick casting of any sort. This is more for research purposes for a book I'm writing. I need two different spells. Basically my main character is a mermaid who was tranformed to a human through magic and lives life in our world. She wears a locket that within has a spell which allows her her to reassume her original form and transform a huamn as well (so as they can survive undert the water) and a secondary spell that allows her to revert herself and the other individual to their respectiive human forms. If you have a spell you could suggest or a site you know of where I could find a spell for either transformation it would be much appreciated.