Here was my experience.

• Called 801 number and CSR said the cert couldn't be extended because I no longer had the credit card. I actually wanted to book a night with the cert that was 1 month beyond the expiration date, but I didn't really get that far in the conversation.
• I booked the night with 25K.
• I then used the Marriott.com contact feature to ask if they could apply the cert.
• 2 days later, a CSR said she would forward it to the appropriate department.
• Today, the reservation is updated. Here is what is interesting. The points are refunded, I also see some activity in my profile related to cert transactions. On the reservation now, it says to call a number since the reservation can't be modified online. I'm happy with the outcome because we intend to stay there that night. It's unclear what happens if I cancel the night (25K points refunded?/or the cert is back??)

I'm really hoping Marriott/Chase change the benefit of the card with the new releases. It can be tough finding a category 5 or below in many cities. The place we were going to use it must have gone to category 6. No problem I thought, I'll use it for another trip, but then that trip is beyond the 1 year mark. I'd be curious if the benefit becomes points each year - or maybe a no AF card that offers Silver, but no certificate each year. IHG's certificate is great and Hyatt's has categories 4 which actually works in cities. I'm sure Marriott already has all of this feedback - so here's hoping that they get a much better deal with the new credit card.