From the WestJet site.
Changes to your flight schedule
Schedule changes are adjustments to flight times and destinations. Unfortunately, even though we prefer not to make schedule changes, they do happen. Generally, schedule changes are made because of adjustments to air traffic routes, airport requests, construction at airport facilities, security constraints, market forces, partner airline schedules and so on.
Should you experience a schedule change, WestJet will make every effort to contact you in a timely manner (via email) to advise you of a change. The email will contain information about your old flight itinerary and your new flight itinerary. Depending on the magnitude of the schedule change, the email may also include the option to accept the change, decline the change (and request a refund), or instructions on how to make a change to your new flight itinerary.
For flights booked directly with WestJet (westjet.com, contact centre, etc.), Please refer to the chart below, which displays how WestJet contacts guests in most schedule change situations.
Looks like you can request a refund if the flight through Calgary doesn't work. You can probably also get them to change the dates if that works better for you. You will of course have to do this through AM which adds another level of complexity to the whole thing. I suggest going on the WestJet website and line up your options. When AM opens on Monday get back to them with option 1, 2, 3. Good luck.
