BUD-AMS-ATL-DFW, LGA-ORD-AMS-BUD late November.

BUD-AMS cancelled, explained I can not take morning flights and only available option was now from PRG
AMS-BUD cancelled, explained I want to leave New York midday from LGA and not JFK and arrive in Europe before lunch, rerouted to VIE.
PRG-AMS cancelled so now leaving 8:50 with about six hours in AMS. Staying on these flights as there are no good seats by the window for two on any flights.

Done within a few minutes. Pretty happy with this, booking flights from BUD saves me thousands and in case of any irregularity DL is willing to switch to 300 miles radius even now. I rather don't want to know how much it would be have I booked this outright.

Sweet secret? I book with Delta even it means I am not in game for Ultimate which I would have probably achieved if I was booking AFKL stock. You get more miles too.