Just booked LH F for a segment about 6 days out...change to a trip originally booked on UA segments (far less than optimal ).

Great UA phone agent, knew about phantom availability and right away told me she would check to make sure it actually exists before she touches my existing flights.

Modified existing PNR. Called Lufthansa right away and they confirmed they have the flight ticketed and provided their PNR.

I was hesitant to mess with this trip with all the SHARES drama, but for me on this instance....so far, worked fine.

Still have to confirm with Thai Airways that the TG segment is ticketed and visible and blessed (or whatever the right term is), but their US office is closed until Monday.