Charmed S4 Ep 15 - Gender Transformations

Season 4 Episode 15 Marry-Go-Round
Later that night, Cole flames into Phoebe's room and chants a spell to curse the face cream. Paige hears a noise, and Cole quickly glamour's into Piper. Paige wonders what was going on, but "Piper" says she noticed Paige was in the bathroom and cautions her that she can't afford to take bathroom breaks while on demon watch. "Piper" also tells Paige she can't afford to go to sleep and promptly casts a spell on Paige to put her into a deep sleep. "Piper" then slips into the real Piper's room, casts the same sleep spell over her, and flames out. Suddenly, Cole turns into the Seer. Piper wants to vanquish the "Seer" on the spot, but Phoebe wants to grill her as well. The "Seer" says she had to stop the wedding because Phoebe would have grown powerful enough to upset the balance between good and evil. She also says that Cole is unconscious in the mausoleum and flames there. In the mausoleum, the "Seer" changes back into Cole; it turns out he shapeshifted into the Seer to throw the sisters off his scent