After seven seasons on Mission: Impossible, actors Martin Landau and Barbara Bain left the show in a salary dispute. Landau was reportedly earning $5,000 per episode, while Bain was earning $3,500. The pair were looking for a raise to $7,500 per episode.
When they didn't receive it, they chose to leave the show.
She was replaced by Lesley Ann Warren (1970-71)
Lesley felt her part was growing after one season and moved on.
Lynda Day George took over and was there until the end of the series