Difference between hcm position hierarchy and position manager
For example, if a position is moved under a different parent position, if there are any direct reports they are automatically reassigned to the incumbent in the new parent position. If there is no manager in the parent position, the application checks for the incumbent in the grandparent position, or until it finds an incumbent. If there are multiple incumbents in a parent position, the incumbent with the longest tenure(service) in the position is assigned as the new manager, You can change the manager to the other incumbent on the Manage Employment page.
If you move a position or remove it from the hierarchy, the grandparent position becomes the new parent position for all the child positions. For example, if you have a hierarchy as follows: Project Manager (grandparent), Team lead (parent), and Developer (child), and you move the Team Lead position to a different branch. The Project Manager position will be new parent position for the Developer position.
But NOT in case of Position Manager