Need change order with dispatch method of EDI to not transmit changes when redispatched

 When I receive an 855 and process the accepted/reviewed change orders, this creates a change order on my PO.  At that point I use the buyers workbench to mass approve these change orders however when I dispatch them, they are all set to EDI (since that was how it was originally dispatched) and this will cause a new EDI file to be created and sent to the van/vendor.  Since the order has already been accepted and sometimes even shipped by the vendor by the time I make a change order, I do not wish to redispatch the po to the