You can reject or cancel orders using the "Void order" feature:
Supplier Hub
1. In Orders, click an order to open the order details page, then select Options > Void order.
2. You'll be asked to provide a reason. Select one or enter it manually, then click Void order to submit this response.
3. Once you have voided the order, the order status will be updated, and the reason is listed above the line items. The customer will also be notified.
Supplier mobile app
1. In Orders, tap an order to open the order details page, then select Respond > Void order.
2. You'll be asked to provide a reason. Select one or enter it manually, then tap Done to submit this response.
3. Once you have voided the order, the order status will be updated, and the reason is listed in the Activity history of this order. The customer will also be notified.