Before an Order ID is processed, it can be deleted to that it is no longer valid to redirect to the checkout.
Deleting a Validated Order
Required Name Value Pairs
UN, PSWD, TRANXTYPE, AUTHKEY, TERMS
Optional Name Value Pairs That Can Be Included In a Delete Order Validation Request
There are no optional name/value pairs with a Delete Order Validation Request
Sample Order Validation Request (In URL)