Complex sentence: It is the first episode to air following the departure of former leading costar Christopher Meloni, and marks the first appearance of Kelli Giddish as Amanda Rollins, who was added to the main cast alongside Danny Pino in June 2011 following Meloni's departure.
Split into simpler sentences: It is the first episode to air following the departure of former leading costar Christopher Meloni. It marks the first appearance of Kelli Giddish as Amanda Rollins, who was added to the main cast alongside Danny Pino in June 2011 following Meloni's departure.