My companion fair code is expiring by the end of December but I have no clear plan to travel due to pandemics. Can I book cheap main fare tickets with the companion fare code now for travel sometime later next year and then change them when I know where to travel next year? I knew Alaska removes the change fees and I will pay the fare difference between existing trip and new trip. However, I am not sure if I can still have the companion fare which will be expired at the time of change.

Thanks.