Originally Posted by skimthetrees

This is married segment availability. Doing a little research- via AA search I can tell you that the NRT-BLR segment is only available when married to another JAL flight (like DFW-BLR via NRT). So you should be able to book a stopover in Tokyo by first booking DFW-BLR with no stopover, making sure that the NRT-BLR segment is on the date you want to travel to BLR. After ticketing, you should then be able to call back and ask them to change the date on the DFW-NRT flight to an earlier date which will create your stopover (the DFW-NRT flight is not restricted, only the NRT-BLR is married). You must, of course, find award availability for all your passengers on the day you want to move the DFW-NRT flight to.

That said, at this point in time, unless you are a Japanese citizen and allowed to enter Japan with their current Covid restrictions there is no way I would book a stopover in Japan this May. You would be risking your trip. If you booked with a stopover and Japan was not open to you, you would not be allowed to travel at all with a stopover. You would need to rebook as a connection which would necessitate you either finding last minute award availability (possible but without researching the likelihood I would not risk my trip on it) or pleading with AS to contact their JAL liaison to have them open availability (there is a fair chance they would take pity on you and accommodate you but do you want to bet your trip on it?).