I'm theory you can change the ticket as many times as you wish during the validity period (probably a year from original ticketing date). Obviously, you can also completely refund a ticket one time.

I do not know how many times you can get away with using the lounge without actually flying, but AA does have a provision in their CoC about purchasing tickets with no intent to fly. I wouldn't suggest pushing your luck.

F tickets are fully refundable and changeable. That is why they are significantly more expensive than other tickets which get you a seat in the F cabin. You may change these tickets as often as you wish and, depending on the country of origin, you may even be able to refund them if you no show and call in after the no show.

At the same time, AA, just like other carriers, has a COC provision prohibiting ticketing fraud such as making a booking which you do not intend to fly. That is most often used against people who make a habit of purchasing a fully refundable ticket as a means to get through a security checkpoint. I suppose that AA might well use evidence of repeated lounge use as internal evidence as well.

In your case, I don't think that the changes you are talking about are out of line with the changing needs of people who purchase full flexibility.

In that situation,. there's no need to rebook the flight for another day just because you need to cancel today's flight. That is, when you tell them you're not flying today, you don't need to rebook immediately - you can just tell them to cancel your reservation and check-in for today's flight and then leave the value on the ticket but not associated with any particular flight. Then, when you you know when you will need to fly, you can then apply the ticket to that flight. This eliminates the need of making a speculative booking that you probably won't need to fly just to have one on the ticket. Of course, with this method, there's no opportunity to use the lounge on the new date that you probably won't actually fly.

Where do you get this stuff? Can you provide one example of AA enforcing said provision against someone who used refundable tickets to get through security?

It's one thing to hold a strong belief that airlines should be enforcing their COCs in the way you think they should; it's quite another thing to hallucinate that it's actually happening.

In the interest of completeness, this is the relevant language in AA's Conditions of Contract (emphasis added)

• Fraudulent, fictitious and abusive bookings: Fraudulent, fictitious and/or abusive bookings are prohibited. These types of bookings are defined as any bookings made without having been requested by or on behalf of the named passenger. Additionally, creating bookings to hold or block seats for the purpose of obtaining lower fares, AAdvantage award inventory, or upgrades that may not otherwise be available, or to gain access to airport facilities, or to circumvent any of American Airlines' fare rules or policies, is prohibited without prior authorization from American Airlines.

Airport facilities would include lounges, but as others have said I can't recall an instance (here on FT) where someone was penalized for that. For creating bookings to block seats, yes (even though it was claimed to be unintentional...) That said, I don't think it really matters what your reason is, because the outcome is still blocking seats that AA could have otherwise sold. So I would imagine a pattern of excessive cancellations would raise flags anyway.

And for what it's worth, Delta does NOT have language in its COC specifically about accessing airport facilities.

Might want to ask them to look into AAirpass for the future.

FT rules prevent discussing how to violate airline policies. The airline has a clear policy of using tickets, without the intention of flying, to gain access to lounges.
While it is normal to make changes to reservation, it would be a bit abnormal to be changing it multiple times after going to the airport and using the lounges.
Or is there some other purpose for this query?

As long as you don't do it 300 times, you might be okay

https://www.ndtv.com/offbeat/chinese...-lounge-549409

Forgot about that one!

This is not AA relevant, but the TWA world club used to be outside security at DCA, I wondered if anyone living very closeby in Arlington might have been tempted to buy a membership just for free drinks. Considering you could bring two friends, could represent substantial savings. The 9 p.m. closing time might have been a bummer though.

why would you not just cancel the ticket and get a full refund?

As far as changes go, as long as it is a fare with no change fee , you can change it free of charge as often as you like

The AMEX Centurion Lounge at LGA is (also) outside security, they require a bp to enter--preventing AMEX PLAT/CENT card members in the vicinity for stopping in for free dining.