someone who has an important position after someone else. Someone who has the position before someone else is called their predecessorsuccessor to: They haven’t yet named a successor to the outgoing CEO.
successor as: His successor as president of the council was Enrique Baron.
find/appoint/choose a successor: the meeting to appoint a successor to Dr. Yates
possible/ likely/potential successor: He had been widely regarded as a possible successor to Kohl.