Charmed (1998)

Season 1: Episode 21

The sisters are about to go on a relaxing weekend getaway to Cabo, when a mortally wounded Leo shows up and asks for their help to save a young woman who's being chased by a darklighter. Desperate to save Leo, Piper casts a spell that swaps their powers, however in doing so, she accidentally swaps the powers of Prue and Phoebe as well. Meanwhile, pressed by an Internal Affairs investigation Andy decides to leave his job in order to protect Prue's secret from being exposed.