You can use the Manage Orders tool to cancel any unshipped order. After you cancel an order, Amazon will send an order cancellation email to the buyer.
Cancel one order
From the Orders drop-down menu, select Manage Orders and follow these steps:
On the Manage Orders page, locate the order you want to cancel.
Click Cancel Order in the Action column.
On the Cancel Order page, select a Reason for Cancellation. You may also enter any information you want to keep track of in the Seller memo field.
Cancel multiple orders
You can also cancel multiple orders using one of the following techniques:
We expect sellers to maintain accurate inventory levels. Failure to adjust your inventory in a timely manner can lead to excessive pre-fulfillment order cancellations. For information on how we factor cancelled orders into your overall performance, see Customer Metrics
Occasionally you may need to cancel an part of an order with multiple items and refund the items that are canceled. Sellers who manage their orders using inventory uploads can submit an Order Adjustment Feed.
To cancel or refund part of a multi-item order, follow these steps:
Ship and confirm all the order items that you can fulfill.
Use an Order Adjustment Feed to submit a refund for the order items that you cannot fulfill. Provide the following information in the feed:
Quantity Cancelled: The quantity that cannot be fulfilled.
Adjustment Reason: The refund code. Select either "NoInventory" or "CustomerCancel."
For more information, see Refund or Partially Cancel Orders—Order Adjustment or Partial Cancellation.