It also says: This offer is also not available to applicants who have or have had this product., and that provision will be enforced.
Yes, always apply without signing in. I assume you have never had the Premier Rewards Gold card?
You cannot "convert" a charge card to a credit card. You will need to submit a new application for the Everyday Preferred before cancelling the Premier Rewards Gold.
No I never applied for the PRG before so I assume I might get the 50,000 sign up bonus? I only have the Costco and Blue Amex cards. Thanks for pointing out about the conversion. Totally forgot the PRG is not a credit card but a charge card.