As a data point, albeit with incomplete information* I have been able to move to an earlier flight with a P fare booking. As for what is incomplete... I didn't check to see what class inventory was available; however the changed flight maintained P booking class.

This was on a MIA-PHL leg in late April.

Wish I knew-- was hoping you might :)

I think the part of the fare rule I posted earlier would suggest this isn't possible:
Usually these fares, if for 2-class F (e.g., JFK-DFW-LAX), specifically exclude the flight numbers that are operated as 3-class flights (e.g., JFK-LAX).

Was a phone agent able to process this for you or a gate agent? When I have called, the EXP phone agent tells me they can only add me to the standby list for a F seat on an earlier flight. But when I get to the gate, the GA tells me I am behind all the Y passengers waiting for an upgrade to F, although I have a F class seat (P fare class) on a later flight as I am a "stand by" passenger and the SDC is only for Y passengers.

Did via web. No agent involvement. Again, this was within the 24 hour SFDC window. Confirmed to new seat in First.

Bumping this question. Any feedback?

Yes, but it often glitches. I've been able to get the EXP desk to help or at check in, but sometimes the system is just stupid.

I had the same experience last week. This week, I plan to call reservations to request my SDC -- I am looking at flights with F availability ahead of time so hopefully this will be a smooth process.

I had this scenario a week ago and no one I spoke to at AA seemed to know the exact answer. Erred on the side of caution, rebooked into business at no charge.

Very interesting that there's no definitive guidance on this, great to hear it was handles the way it was! :)

Just as a data point, I was on an international itinerary with the last leg being a JFK-SFO "D" fare. When I got to the airport I was many hours early and asked if I could get on to an earlier flight. "D" was available but they insisted I had to pay a $100 change-fee, they even checked with several phone support people.

Oddly enough, once I paid the $100 fee, online it offered me the option of SDC'ing to the later flight I just moved from at no cost. :confused:

It sounds like I shouldn't have had to pay the $100 fee.

Same day standby [on MileSAAver award]
 

Are same day standby requests possible when travelling on a milesAAver award?

Thanks in advance.

Do you mean "same day confirmed" or "standby"? The basic answer in either case is that it makes no difference if travelling on an award, i.e. it is possible subject to the other restrictions such as domestic-only and not on partners.

Specifically; paid discounted business class, upgraded to F using Miles (15,000) plus fee of $175. JFK-LAX on AB321 4 class. Can I stand by for an earlier flight on F same day ? Can I pay the $75 for a confirmed earlier flight same day ?

Standby for an earlier flight yes; same-day confirmed no, because SDC is for main cabin.