I have another flight from YYZ -> YVR -> ICN coming up. Since we have the SWU promo for domestic flights, it may make sense to use a SWU for the domestic leg and the SSWU for the international leg just in case the second upgrade does not clear at the gate. I am rolling in SWU certs so I am not too worried about burning an extra SWU.

Is this even possible or will they ask for a SSWU @ YYZ? They are two different flight numbers but on the same ticket number.