Originally Posted by
demue
A free change I can see too, but if OP wants to change to / reroute on
a partner flight where YQ is applicable, he'll have to pay that, no way around it. Hence best to try to stick to SQ routings.
I am actually on defense on the YQ.
Because the ticket in question has been issued, OP should not even be liable for any additional costs, including YQ, if involuntary change is required.
But the problem is SQ does not fly to Canada, so SQ is not required to file international tariffs with TC.
Bottom line, we are in a he-say-she-say situation that OP will eventually need to pay for the YQ.