Click on the 'Employees' on the main menu
Go to Line Managers
Select the Line Manager you want to replace and "click" on the action.
On the action, you will have the option to replace and view employees reporting to them.
Action That can be done
If you are replacing the line manager, you will have an option of selecting the new line manager to replace with, you can also view all the employees that were under the old line manager who will now be inherited by the new line manager.