To remove all of the manager’s buyers, sellers, and assistants: first select the personnel's corresponding role that you want to remove, then press the "remove" button in the menu bar or right-click and select the “remove” button to remove. Assign corresponding buyers and sellers: refer to How do I assign corresponding buyer and sellers to employees? to change the responsible buyers and sellers.
To remove a specific manager, you first must remove the manager’s assistants, buyers, and sellers in order to reassign to a new manager.