Important things to keep in mind:

• You can only cancel a label if the manifest has not been filed yet. If you need to cancel a label for an order in an already filed manifest, please contact the Courier directly.
  
  
• A label for a Processed Order can only be cancelled in the Shipping Manifests screen. After cancelling a label for a processed order, you will not be able to change the shipping service. To print a new label with a new service, please create a resend order and select the shipping service you wish to use.
  
  
• If the order has been deleted before the label was cancelled, you will receive the following error:
  Unable to find order ID
  To cancel a label for a deleted order, please contact our Technical Support.
  

The full documentation page for cancelling shipping labels is available here.

To cancel a shipping label:

1. In the Open Orders screen:

If the order is still open, then you can cancel the label when you select the order > right-click or Actions > Shipping > Cancel Label

2. In the Shipping Manifests screen:

A shipping label for both an open and a processed order can be cancelled also in the Shipping Manifests screen if the manifest has not been filed yet:

Shipping > Shipping Manifests > View on the needed courier line > View on the needed service line > Cancel on the needed order line.