Welcome to Flyertalk @
Melissa Melendez and good luck with your adventure. Escalation can help; but I'm not very optimistic that you'll have success with this. What is the routing you had? Can you overnight in SEA? Maybe AS can put you up in a hotel there so you make your downline connection.
AS is extremely inflexible with companion certs. Even "day of" disruptions I've had them unwilling to move me to other carriers when on a companion certificate. Glad you saw this with some advanced notice ^