When changing flights on the same routing, keeping them on the same carrier's flight number prevents a reissue and the related charge. Unlike OW tickets, same city pair but different airline on *A triggers a reissue. Or at least such as been my experience.

I'm surprised that there was any issue on an NZ-issued ticket and an SQ flight, but the fact that there was an issue with a CA flight booked as an OZ codeshare doesn't seem that odd. I think CA and FM have major IT issues... Both have been UA partners for a while, but I recall having seen posts in the UA forum about CA not seeing award reservations booked through UA.

I personally had an issue with FM on a UA-issued ticket (FM didn't have a reservation for me where UA said there was one), but fortunately this was a PAPER ticket and so there was no question about the ticket's number or validity.

lokijuh, I do sympathize--I was nearly stranded at JNB myself one time because LX couldn't see my ticketed reservation that UA saw having been confirmed. It stinks, and the only thing I can suggest is to complain loudly to the issuing carrier.

seanthepilot is totally correct--airlines need to take more responsibility when it comes to e-ticketing!