Complex sentence: When Hartnell asks Newman for a reduced workload, he learns that he is to be let go and the Doctor to be played by Patrick Troughton through plot device Harnell struggles with his emotional attachment to the character but reluctantly accepts the decision for him to leave.
Split into simpler sentences: When Hartnell asks Newman for a reduced workload, Newman tells the actor that he intends for the show to continue, but without him in it; he is to be replaced by Patrick Troughton. He struggles with his emotional attachment to the character but reluctantly accepts the decision for him to leave.