In case you need to change the purchase order holder from the one you entered when ordering, navigate to Financial Management → Order Managementi and click the icon Manage installments and payments on the specific order line.
Click the blue icon next to the current order recipient and choose the new one from the drop-down menu.
N.B. The possible choices are the student enrolled in the course and the guardians/responsible persons (e.g. father and mother) connected to them in the registry.
Click the green save icon to save the operation.