American Airlines processes domestic upgrades based on an elite member’s status and how close they are to flight departure. For instance, an Executive Platinum (100,000 mile) member can be upgraded from a coach ticket to domestic first class ‘up to’ 100 hours before departure, provided that upgrade space is available.

Upgrades are booked into the “R” bucket of inventory. This bucket was hidden. You couldn’t look up whether or not R was available to know whether an upgrade should process unless you were in American’s own systems.

Since mid-June month, however, American has started to utilize R both for revenue fares and for upgrades. That means R inventory is now ‘published’. Here, for instance, R is available even when there’s just 1 first class seat for sale in the cabin. That’s because it’s now the second highest bucket of first class.

Adding R to the list of first class domestic fares gives American greater flexibility and granularity to price how much they sell first class seats for.

What’s interesting is that just because there are seats available in R and upgrades book into R in fact R being available doesn’t mean you’ll get an upgrade . There are people waitlisted for upgrades on these flights even though R is available, and requesting an upgrade on one of these flights won’t get it auto-confirmed.

Furthermore, just like American does with the “A” fare bucket where they use it for paid fares and upgrades, getting an upgrade into A doesn’t mean you’ll earn miles at the upgraded cabin rate and getting an upgrade into R doesn’t mean you’ll earn miles on your coach ticket as though you’ve paid for domestic first (according to internal documentation, “QIK CHK and automation will attempt to re-add the applicable upgrade SSRs if an upgraded customer is rebooked into R class”).

So does anything really change, and why am I mentioning this minutiae? You can’t use the availability of R inventory for sale to predict an upgrade, so what use is it?

It turns out that,

Historically when you received a complimentary upgrade but changed flights (by choice, or when your flight gets delayed or cancelled) you weren’t supposed to keep your upgrade. If you had paid for coach you’d be put into coach and waitlisted for an upgrade. (Of course some agents have been more generous than this, but that’s how it was supposed to work.)

Recently there have been several reports that customers are retaining their upgrades when changing flights if they’re booked into R from a complimentary upgrade and R space is available on the flight they’re rebooking onto.

This change has been consistent in reports whether confirming a same day change to an itinerary, or swapping flights during irregular operations using the American Airlines app. Presumably because American sees you in R and is simply rebooking you into R, and R is now far more available since it’s been given a dual use as the second highest first class fare class.