Same problem from a couple weeks ago is back again.
Currently have MLE-AUH-LAX-ABQ booked as a J award. F availability opened up on the AUH-LAX route. Called US, Australia & Singapore and none of them could see the F availability when trying to modify the existing reservation. HUCA a few times with Singapore with no success. Asked for them to search it independently and they see availability which i put on hold with its own record locator.
Two weeks ago after 6x HUCA I was able to get a CSR to talk to a supervisor who was able to do a ticket exchange to bring together flights in two separate record locators when making my reservation to Abu Dhabi. I've tried calling 3x today and each rep looks at the record locators, calls the help desk, then tells me they can't do anything. They say they can't bring them together without either cancelling the MLE-AUH segment in one locator or the AUH-LAX in the other with no guarantee that they will get returned back to inventory.
I'll try calling again later. I might just try to build the flight itinerary the next day in F. Over the past few weeks there have been several people, myself included, that have had a difficult time upgrading EY award tickets after the reservation was made. The CSRs are seeing limited availability on alternative flights when trying to modify the existing reservations but can see all of it in a new independent reservation.