Bit of a horror story, have (or now maybe had?) a great OWA in J booked for over the new year. Decided to drop the last segment, a Qantas flight, and add an American segment in the middle (which was originally booked as a separate ticket). Called up and got it changed and all looked fine.
Checked an hour later and 4 Sri Lankan segments had been cancelled, apparently automatically by their IT system. Called up and 3 were able to be reinstated because award availability was still there, one segment sent to the oneworld desk to get reinstated.
Checked another hour later, and because all the UL segments had been cancelled, MH decided to cancel all four of their sectors. Called up again and exactly the same, 3 reinstated on the spot, 1 sent as a request to the oneworld desk.
Operator said tickets had been issued, paid for and confirmed, so without saying guaranteed, did say high chance they will be reinstated. But with less than 10 days to go to the initial flight, little bit annoying. Apparently the oneworld desk also operates business days only, so 48 hour response takes me to Monday rather than today or tomorrow. Would have thought something important like that would operate weekends as well!
Wish I understood how adding a completely unrelated segment would cause another carrier to cancel their segments!