UpdateOrder

Summary

Change the contents of an Authorized but not Captured order. Use this call to add or remove items in an existing Order, without creating a new orderNumber.
You must provide the entire body of the query, in the same format as Authorize, including all Order Items. (If you added an item, Update Order must contain previously Authorized items as well. If you removed an item, Update Order must contain the new full list of Order Items.)
If the TotalGrossAmount has increased compared to the Authorize call for this orderNumber, a new Risk Check will be made for the additional amount. If the additional Risk Check returns a rejection, the original Authorize will remain valid.