Freaky Friday (2003)

A tomboy teenage girl, Annabel (Lohan), and her widowed mother, Ellen (Curtis), who are always arguing with each other, simultaneously wish they could be someone else, they somehow exchange bodies, as they both learn (or in the mother's case, remembers) what it's like to be in the other person's situation. As nice as that might be, the duo faces a deadline, as the mother is due to get married soon, and doesn't want to miss the big event (obviously) or for her daughter to get to know her new stepfather (Harmon) a *lot* better than she had expected... There's also the problem of Annabel finding herself stuck with her mom's job as a medical doctor (but without any of the training to back it up)!