If you downgrade to no-fee arrival they won't know you had the card before. The system will reject the app because it knows you had it and won't pull your credit, but call recon and you will have a convo like this (I jad it multiple times):
Rep: how can I help you?
Me: I applied for usair and it's pending - can you take a look?
Rep: Sure. Actually, you can't get this card because you already had it, and your credit wasn't pulled as a courtesy. Wait, that's not right - you did not have it. Hmm Strange why the system says that. It does that sometimes. I can take a look at your app, but I have to pull your credit, ok?
Me: Sure.
Rep: (after some time) Ok, I looked at your credit, I see you have the no-fee arrival that you did not use much, so I'm not sure we could give you more credit, but I can close that card for you and approve you for this one (or if they do want to give you more, they'll just approve you.
Rinse repeat - well not so much anymore. One rep transferred my credit from the arrival to approve the usair and added 1k credit because "you need a minimum of 5k to be approved for this card". Next day my wife was approved for 1.5k - ntm, it was a 4k cl that was originally a usair card
Maybe this info shouldn't be publicized, so they do't fix their system?