Who was the manager that replaced George Martin for the Beatles?

George Martin was never their manager. He produced nearly all their records. He began declining sessions with them in 1969, after the Get Back project turned into a squabblefest. Alan Parsons served as de facto producer at some of their last sessions. Martin returned to make Abbey Road with the band, after they agreed to set their differences aside, and make an album "like in the old days", with Martin fully in charge. Phil Spector did post-production on several of the Get Back recordings, which were ultimately released as Let It Be in 1970.