Someone's successor is the person who takes their job after they have left. 继任者
noun [专属名词] 继承者,接替的事物;(组织、机器等的)接替物
He set out several principles that he hopes will guide his successors. 他制定出了几条原则,希望能指导其继任者。
He set out several principles that he hopes will guide his successors. 他制定出了几条原则,希望能指导其继任者。