I was able to rebook my ticket from March to June. Still within one year from my outbound flight. All the agents I spoke with wouldn't extend the ticket validity beyond one year. I also rerouted from YVR to JFK since first class is no longer available on the YVR route. I did have to pay the additional taxes and fees, it was a little over $200 USD. I haven't received a receipt yet so I'm not sure of the price breakdown.