Used the EK one way tonight for the first time. Surprise, surprise. Found and booked two First (Z) seats JFK-DXB (A380) connecting to DXB-JNB (one First and one Business (D)) in October. Was told that if Z opens on my DXB-JNB flight, I could change to First without having to cancel/rebook.
On the other hand...
EK would not let me cancel the IAH-DXB portion of a roundtrip and let me keep the DXB-IAH return without canceling the entire trip and starting over. Needless the say, the two DXB-IAH First seats did not go back into Z inventory. No biggie as I had already protected myself on an EY First flight the same day.