post https://marketplace.walmartapis.com/v3/ca/orders//cancel
You can cancel one or more order lines. You must include a purchaseOrderId when canceling an order line. After canceling your order, update the inventory for the canceled order and send it in the next inventory feed. The response to a successful call contains the order with the canceled line item. Cancellation reasons supported:
- CANCEL_BY_SELLER
- CUSTOMER_REQUESTED_SELLER_TO_CANCEL