I can say with certainty it can be done...
Last year I was scheduled to fly YYC-YVR-SEA-YVR-YYC
for reasons too long to explain I wanted to drop the YVR-SEA segment.
I called to ask they said no because it would cancel the remaining segments.
I asked a gate agent at YYC they said the same thing.
I asked customer service at YYC they said the same.
I got got to YVR and asked a customer service agent and they were able to do it after not an insignificant amount of groveling.
I told my partner (the reason behind the change...) that if I was one segment short I was going to make her pay for my mileage run...I was in fact one short and she did pay for me to be the only passenger on a YYC-Red Deer flight!
also fun story...crossing the border in a rental vehicle when you were scheduled to fly across made for an interesting conversation in the nexus lane with the nice border officer...
Last edited by RLPYYC; Jan 25, 2019 at 12:52 pm