Grazie 
thank
note 499918
These functions are not provided.
According to the SAP concept, the change options in the billing document should be reduced to the minimum (for example, tax classification -> account determination) and the required changes should be made in the sales order or delivery document the billing document is based on.
note 43296
There is no standard solution for the following customer requests
but it is strange that the exchange rate of the courier invoice is enabled by SAP.
it seems illogical to reverse a bill to change the courier (which has no impact on accounting data) and it can happen that in an invoice needs to be modified at the last moment to change the courier.
thanks for the time dedicated to me