Short Answer 
Natascha McElhone left *Designated Survivor* due to creative differences and financial negotiations, leading to her character’s unexpected death at the end of Season 2. Her departure shifted the show’s focus to Kiefer Sutherland’s character, allowing for new storytelling possibilities, while McElhone has remained silent on the reasons for her exit.
Step 1: Understanding the Departure
Natascha McElhone left her role in *Designated Survivor* due to significant creative differences with the show’s production. Her character, Alex Kirkland, was written off, dying unexpectedly towards the end of Season 2, despite McElhone’s desire to continue her involvement in the series. This change represented a dramatic shift in the show’s storyline.
Step 2: Negotiations and Outcomes
After expressing her wish to stay on the show, McElhone requested a salary increase to continue portraying her character. However, ABC was unable to meet her financial demands, leading her to ultimately decide to move on from the series. This situation highlights the often challenging negotiations that can occur between actors and network executives.
Step 3: Impact on the Show and Future Directions
Following McElhone’s exit, ABC issued a statement wishing her the best in her future endeavors, while the show pivoted to focus on Kiefer Sutherland’s character ascending to power. Despite fan disappointment over McElhone’s departure, it opened new avenues for storytelling within the series. As of now, McElhone has not publicly addressed her exit from the show, keeping the speculation regarding her decision alive.