Originally Posted by
jsloan
Huh? No-charge SDC always depends upon the same fare class being available. Flexible vs non-flexible is irrelevant.
Availability changes constantly, in both directions. It's not uncommon to see flight inventory disappear, nor is it uncommon to see it reappear as plans change. Also, in order to do an SDC, you need to be within 24 hours of both flights -- the one you're on now and the one you're targeting. It's almost impossible to move a flight 24 hours ahead in one SDC, because by the time you're eligible for a change, you've no-showed your existing flight.
The core question -- still unanswered, in my opinion -- is whether or not there are recent experiences with this given that the app is seemingly no longer showing next-day options and you'd need to call to make them.
I remember, in March 2019. I was going to fly LAX-IAD on a red-eye on Sunday on an L fare. However, last minute, Monday morning at 08:00 am, an important event has been scheduled and I needed to attend. So I've changed my flight to the 1:00 PM departure on Sunday and obviously there was no L fare ( discounted Economy ) available.
I am %100 sure that United won't sell $139 walk-in tickets for a transcontinental flight on a Sunday which was fully booked at the time we boarded. I had no issues transferring my flight 24 hours before my originally booked flight. I have also intended to take the 787-10 to EWR and connect to a regional plane ( which would depart around Sunday 09:00 am and arrive at the same time with the 1:00 PM direct ) but I wasn't able to change for that specific combination even it was bookable via united.com. Then I individually checked every flight on the SDC list with the bookable options and in the SDC list, only "all" flights that had Economy Non-Flex availability were visible on the SDC list.
I would fly United next week ( Friday ) and being relied on to the SDC process, I bought a cheaper option from my origin to my destination in L fare as the flights that I am intending to take had only Q class ( or expensive fare classes ) available at that time. I would check the fare availability at expertflyer once I have changed my flights and report it back here.
To answer your core question, that Sunday morning I was able to see Monday 06:00 AM-08:00 AM departures on the SDC list.
However, I would re-answer this core question with screenshots next Thursday or Friday.