I want to change my flights after the first flight but I am not sure if the flights are available. When I use ita matrix and restrict it to booking class D, I see there are tickets available in D but when I use oneworld page to book a new ticket that includes the flight segment, it doesn't show up. Does it mean that this particular segment is not bookable via DONE4? For example, I am trying to book HND-LON on JAL but on certain days the flight does not show up on oneworld page but D class is available on ita. Similar issue with CX for inter-asian flights. Oneworld shows only a limited number of flight combinations but ita shows nearly all...