Originally Posted by Recurve

Just to add on, a few months back I tried to book a mixed cabin itinerary that I had created on Matrix, it was a four-leg multi city itinerary on AF/KLM (no DL codeshare on any of the legs), and Delta.com was able to generate the itinerary using Matrix Power Tools (someone linked above), but not in the correct booking class. When I called the DL GM line, they were able to book the itinerary even though there were no DL flights involved, it seems that the DL GM line can book AF/KL flights as well.