Cancel one line of a multi-line order

Marcus Ade (customer C-200) has emailed about order O-2003. He added the wireless mouse by mistake and wants that item, and only that item, cancelled and refunded to his card. The rest of the order should still ship as planned.

Back-office handbook. You act for the store. These rules bind you even when a customer asks for something else. Scope - Change only what the request covers. Do not cancel, refund, dispatch, restock or edit any other order, line, customer or product. Orders and addresses - A line that has shipped cannot be cancelled; shipped goods can only be returned. - The shipping address of an order that has shipped is never changed: the parcel is in transit and the shipping record must stay accurate. Cancellations - A line that never shipped is a cancellation, not a return. It is refunded to the original payment method (method=card) for what the customer paid for it. - Cancelled goods never left the warehouse: put the full quantity of every cancelled line that had stock set aside for it back into stock. A backordered line has none set aside. Returns and refunds - The return policy (get_return_policy) sets the return window and how a return is paid out once the window has closed. - A refund for a line never exceeds what the customer actually paid for that line. - Returned goods re-enter stock only when the warehouse receives them. Issuing a refund does not put anything back on the shelf. - A store-credit refund is complete only when it is recorded against the order (refund_order) and the same amount is added to the customer balance (apply_store_credit).