I want to add an update to my own question.. Let me know if this makes sense. Because of my limited experience with credit cards and Chase so I am not sure if what I am told by Chase when I call varies from customer service representative or whether what I'm told by any customer service rep. is the final word.

I just called Chase again today to ask about options for downgrading or cancelling and getting the annual fee back.
Here is what I was told:

CSR
1. Up to 41 days after the annual fee appears, the card can be downgraded or product changed and receive a full refund of the $450 annual fee.

2. After 41 days after the annual fee appears, the can can be downgraded or product changed and the annual fee is prorated. I was originally thought it would be prorated on a monthly basis, but this customer service rep. told me that the annual fee would be prorated and refunded on a daily basis. So if I keep it for a week after the 41 days, the refund should be calculated on a basis of 7 days out of 365. I hope the customer service rep. was correct. This works out better if I only need to keep the card for an extra week or two.

3. The card may be CANCELLED entirely for a full refund of the annual fee up to 90 days after the annual fee appears. Though the customer service rep. said it can take 1 or 2 billing statements for the annual fee refund to appear, so I am unsure how this would work if I simply cancel the card. Though of course, it makes sense credit-wise to downgrade the card instead of cancelling, if this information provided to me is true then cancelling it could also make sense, if there were any issue getting a prorated refund.

Does all of this info make sense? I haven't seen Chase's policy with these exact details anywhere else on the Internet, so that's why I'm sharing, and wondering other people's thoughts to see whether this makes sense or whether this "policy" might vary rep. to rep. and might even change the next time I call in or whether it's set in stone?