Originally Posted by
KhemaneyBoy
From my experience, those are generally not blocked off to Diamonds. Recently flew from LHR-HKG on J. Was looking to change my flight from CX254 to CX252, and was able to see that all window seats were available in the mini cabin on the CX252. Unfortunately, wasn't able to change my flight, but I was able to reserve 12D on CX254 well before the date of travel. I only have CX silver status.
That was my experience for years, Tried to book a September itinerary and a December itinerary, and both had the mini cabins blocked to golds on both directions (they would release to Diamond but not Gold). Since I purchase fully refundable fares, for now I booked on another carrier.
Will check later or a different agent if they open up.