Well, this is getting super subtle, but I think they *do* change the fare class of the sector as displayed on the eticket. And I think they *do* revalidate the ticket. I think of this colloquially as issuing a ticket and I think it's fair to say you are "ticketed in R" after an upgrade — here's why.

Suppose I book a 3/15 award flight SFO-LAX then call UA and change to the 3/17. They'll revalidate (same e-ticket number) but they will change the departure date of the SFO-LAX sector on the ticket. Colloquially I think of myself as having a ticket on the 3/17 trip — and a "send me my e-ticket" e-mail from UA would agree. They have changed the data on their e-ticket and revalidated it.

Or suppose I book a 3/15 award flight SFO-LAX-LAS with first sector in "I" and second sector in "X". I'll pay for a business-class award trip. If saver business opens up, I might call UA and change from "X" to "I". They'll revalidate (same e-ticket number) but they will change the fare class on the LAX-LAS sector to "I" to reflect that I'm now ticketed in business. Colloquially I think of myself as having a ticket in business on the LAX-LAS trip — even though the originally issued e-ticket showed "X" for that sector, a new display of that e-ticket info will show "I".

So you're right to say that UA rarely "issues" a ticket in "R" since they don't start there. They normally first issue the ticket in a revenue booking class, then change the existing ticket. But they can "reissue" a ticket for other reasons that can cause the revalidated R to be visible to other carriers (as mentioned above).

And I certainly think it's fair to say that when upgraded, you are "ticketed in R" inasmuch as you are "ticketed on 3/17" after a date change from 3/15 to 3/17, or as much as you are "ticketed in Business" after changing one sector on an award ticket from coach to business.

If you want to see something totally crazy re: e-tickets and upgrades, check out what SAS is doing with their partnership with optiontown.com, http://www.flyertalk.com/forum/sas-e...rades-sas.html. You pay this vendor a bidded price for an upgrade. These guys (who are set up as an online travel agency) exclusively handle already-issued SK tickets. They take control of your ticket and change the booking class to some kind of paid J bucket that accrues more miles and do an e-ticket exchange, all via some shady backdoor mechanism. If you need to make subsequent changes to the trip, you need to call this phony "OTA" and get them them to give control of the e-ticket back to a real agency or back to the airline. Crazy. Their solution to "upgrade" non-117 stock tickets is to add some free text to the reservation as supplemental information saying, basically, "this customer paid for an upgrade, please seat them in J" that is supposed to be respected at check-in time at the counter.