plastic surgery, after having her arm severed. Meredith is assigned to work for Sloan during the day, and is immediately told to find the arm, much to the fascination of her interns. Despite trying to deal with her trainees in a strict manner, Stevens is looked upon as unprofessional by the interns she was assigned to. Her image is further deteriorated when she decides to abandon her hospital duties, in order to perform surgery on a deer, once again letting her emotional involvement interfere with her career. Meredith and Shepherd discuss the repercussions of their breakup, and realize that they cannot reconcile. However, the two engage in sexual intercourse, as a manner to express their mutual feelings for the last time. O'Malley comes to the realization of his love for Stevens, and quickly discloses to her that he shares her romantic feelings. Production "A Change Is Gonna Come" was written by series creator and executive producer Shonda Rhimes, whereas filmmaker and series veteran Rob Corn served as the director. The soundtrack used in the episode included Mat Kearney's "Breathe In, Breathe Out", I'm from Barcelona's "Oversleeping", Meiko's "Reasons to Love You" and Cinematic Orchestra's "To Build A Home". Also featured in the episode was "Knock 'Em Out", the second track from British pop singer-songwriter Lily Allen's debut album, Alright, Still. Several one-time guest stars appeared in the episode, including Mark Pellegrino, who played Chris, Stephania Childers, portraying Nancy Walters, Sandra Thigpen in the role of Clara, and Steven Porter, who acted as Joey. Although fictionally set in Seattle, Washington, filming primarily occurred in Los Angeles, California. Scenes in the operating room were filmed at the Prospect Studios in Los Feliz, Los Angeles. The season 4 premiere saw Leigh's first appearance as a main cast member. Leigh first appeared on the show during the last 3 episodes of season 3 as Meredith's half-sister, Lexie. Following Washington's departure, it was reported that show's executives were planning on adding new cast members, such as Lexie. She was officially upgraded to a series' regular on July 11, 2007, for season 4. On casting Leigh as Lexie, Grey's Anatomy creator Shonda Rhimes stated, "We met with a lot of young actresses, but Chyler stood out. She had a quality that felt right and real to me. It felt like she could be Meredith's sister, but she had a depth that was very interesting." Leigh offered