A reversal of position is called an inversion. If a bookstore's employees join together to purchase the store, there's an inversion of power: the employees become owners, and the former owners are their employees.
Reversing the normal order of words in a sentence is also an inversion, especially if the verb comes before the subject. This inversion happens naturally in questions like "Are you happy?" but in statements it can sound a bit like Yoda from "Star Wars" — "Happy are you." In weather terms, an inversion occurs when the air temperature near the ground is colder than the upper air temperature.