CancelShipment Method
Cancels a shipment.
Syntax
int CancelShipment(char* lpszShipmentId);
Remarks
This method cancels a shipment. The ShipmentId parameter is the value returned by the ShipmentId property when GetPackageLabel was called.
Note: This is only valid for shipments created using a contract (e.g. when CanadaPostContractId is specified) and must be called before TransmitShipments has been called for the specified shipment;