Shapeshift

Shapeshifting is a generic catch all term for transforming, but in this case it specifically means transforming into a form similar to your original. So if you are a fat guy transforming into a skinnier version of yourself that would be covered here. As well as transforming to another person who matches your gender like a man transforming into George Clooney.

Typically shapeshifting is found as a natural ability by a lot of supernatural entities. For instance a succubus can transform into any beautiful woman.

Sometimes it is part of a potion or device. The amount of ways to cause change via shapeshifting are many.

Typically the reason behind changing another person is to disguise yourself, but it could be used to enhance yourself as well. An ugly woman might use this type of transformation to become beautiful. An elderly person might want to relive being in their 20’s.