I could not do an SDC on one of my recent trip.

The ticket was business lowest. HKG to YVR to YYZ to BOS. Booked using a FTC (outbound travelled with inbound cancelled). This trip involves an overnight layover at YYZ, which I wanted to eliminate by taking a redeye YVR-YYZ flight instead.

When the first flight was open I requested the SDC via concierge. They could not do it and asked me to try again when the YVR flight was open. I did so and they still cannot do it, saying the last flight was not open. I took my HKG flight and requested again when the last flight was supposed to be open, and the concierge desk still could not do it, due to an “open jaw not allowed” issue. By then it was a moot point since the redeye flight I wanted to take had already sold out in J.

I suspect that the open jaw was the root issue. This was quite disappointing experience.