The problem I see is that they're going to have issues if they take the 777 off a route and put an old 747 on the route, as passengers will have booked expecting flat beds and wind up with angled. Maybe if they take a route with few seats booked very far in advance but with significant close-in demand, they can make the change, toss some SkyPesos to those already booked as compensation for the equipment swap, and then sell further seats at a discount (since more seats to sell, but with worse product, especially if up against a better hard product)?