Not sure how it works on Cathay, but can one typically standby for an earlier flight on the same day?

Or to ask an even more specific question:

If I am flying HKG-PVG, CX metal, KA flight#, AA ticket stock, can I standby on an earlier KA flight HKG-PVG?

It depends on the fare rules of the ticket. CX/KA have 3 levels of changeability (if that is a word)

1 - Can't be changed
2 - Can be changed for a rebooking fee
3 - Can be changed, no rebooking fee.

Typically, I would expect an AA ticket to be on a high enough fare basis to be either 2 or 3.

are you on an award ticket?

Normally for HKG-PVG (or PVG-HKG for that matter), if you are travelling on CX/KA ticket stock, even on the most restricted non-changeable ticket they will be quite happy to change you at no cost to an earlier flight if seats are available when you turn up at the airport.

However, you are issued on AA stock, and I'm not sure if or how that changes anything.

Thanks for the information. No it is not an award but a regular revenue ticket. Low fare class though, on the AA side at least it books into N.

So at least in general you could go from a CX flight to a KA flight?

This is a good question. I have always been able to change to earlier or later flights on the same date with NO ISSUE WHATSOEVER if there's a seat open. So that's that. However, I have never change from CX metal to KA metal or KA metal to CX metal. In theory it should be all the same and especially now they are codeshare with one another anyway, however, do report back your experience.

I did that for TPE-HKG on a CX ticket last December, I decided to change to an earlier KA flight at the airport on the day.

It depends on ticket rules.
I was denied an earlier flight last week in TPE on a V class ticket. Says ticket rules not permitted.
I've been denied in HKG to PVG for an earlier flight too, also citing ticket rules not allowed.
Only place IME that doesn't care about ticket rules is PVG. No problem moving to other flights regardless of ticket type.

AA stock has little bearing in the whether the ticket can be standby or not. It only means ticket# starts with 001 nothing more. One can buy a CX fare on 001 stock and it would have the same rule as one issued on CX stock.

Good point, I believe the ticket is for a fare published by AA (N class).

I have a related question - does CX/KA oversold J if there is no F service (i.e. they cannot opup J to F when not enough seats in J)?
I want to know the chance of stand by got cleared when it shows J0 - if there is no oversold, one no show will free a seat for stand by.

It does have some bearing on how flexible a GA may be on what they would do. Once on a MAN-LHR segment, I wanted to take an earlier flight (AA 001 stock, BA metal of course). The comment was that while my fare didn't allow standby, she normally would have just exchanged my ticket for the early flight anyway had it been on BA stock, but since it was AA's stock she couldn't/wouldn't do anything for me. YMMV

I have never done it from Hong Kong - so can't help you there, but every time I have asked at PVG they have put me on an earlier, except once. Award tickets, most restricted ticket - they really do not care.

Actually, one time I checked-in and the lady asked if I wanted to take an earlier flight - I said no as I wanted some time in the lounge. Once I got to the lounge, same lady calls my HK cell phone and says that my flight is delayed and would I like to take that earlier flight now? Of course, I said yes. Someone came and got me, took me to immigration (In China they have to know exactly which flight you left on so swapping without telling them would be illegal) and ran to the gate. Was the last person to board and was upgraded to J. When I arrived in HK - my original flight was so not delayed.

PEK is the same, but once I changed from KA to CX and they said they had to charge me the RMB600. I had another flight to get so I paid it.

Actually she could....if she was trained/or wanted to. On day of departure, operating airline has control of that flight coupon. They could have just booked you on the new flight without having to exchange it (or just issue a new ticket on BA stock and submit the original flight coupon to AA for settlement as they normally do).

The plating carrier (AA in this instance) doesn't care how the other airline is going to fulfill transportation. The only involvement AA has at this point is paying the ticketed airline when that coupon is submitted for settlement.

For example, if the flight coupon is for HKG-PVG on CX123 and CX ends up sending the passenger on another CX flight (or another airline for that matter), AA still pays CX as indicated on the flight coupon.

side note: nice usage of this term