I'm advising a passenger who was ticketed to fly SEA-LHR on an AA(BA) codeshare, in paid first class. With ~six weeks notice, BA canceled the late departure (~7pm). AA sent an email saying no alternatives available. GDS shows a BA departure at ~1pm (with some first class inventory left), as well as a Delta flight (only business class; no first cabin) also at ~7pm.
Passenger prefers the time booked in the cabin booked. That's why it was booked this way! If passenger has to choose between departure time and cabin, passenger chooses time.
A first question is whether AA (the marketing carrier for this segment) will even endorse passenger onto Delta. At one point AA and Delta fought about irrops handling. Looks like that's now
resolved.
A second question is what refund and/or EC261 compensation if any is due. A move from AA(BA) first to Delta business is a downgrade, so natural starting point is 75% of the affected segment. I suppose BA could argue that it had a first class seat available on the 1pm flight, and passenger should have taken that. Indeed, with 6 weeks notice, BA might argue that no benefits are payable under EC261 for the cancellation of the original flight or significantly different time of the new flight.
Of course passenger would be entitled to the fare difference. But we all know the many ways to calculate fare differences. Risk of AA calculating this to be next to nothing. Undeniably the AA(BA) fares that book into A cost only a bit more than those that book into I or R, if a customer has the right advance purchase, min stay, etc. and if inventory is available. Could be a very bad deal for the passenger, who had gotten a great price for first but instead ends up charged a rather poor price for business.