I am trying to link two link itineraries, the first one YVR-NRT(AC) and the second one NRT-TPE(ANA), on two different tickets. This way if my first flight is delayed, the 2nd flight will be notified(i think?) of the late arrival and hopefully it will not be a NO SHOW.

I talked to the reservations agent and they said they can cross reference the two reservations without any problem. However, I want to wait until I check in for the YVR-NRT flight before linking the two reservations so that I can check in 24 hours before the departure of first segment rather than 24 hours before the final segment to maximize my chance for the upgrade standby.

Anyone knows if I can still cross-reference the two itineraries after checking in on the first flight?

Thanks!