Bewitched S4 Ep 4 - F2F Transformations

Season 4 Episode 4 Double, Double, Toil and Trouble
Darrin makes Samantha, who is in the midst of performing her duties as Queen, end a royal session early. The following day, while Samantha is out all day doing volunteer work for the church bazaar, Endora and her friends enlist Serena's help to seek revenge. Serena passes herself off as Samantha and tries to drive Darrin away in hopes of ending the marriage. Because of Gladys Kravitz, the masquerade begins to unravel.