Tinky, were they saying that she could not upgrade LAX-SYD (the V fare) or the DEN-LAX? or the DEN-LAX-SYD? The V fare, if it was purchased from a consolidator could well be treated by UA as a bulk (private) fare, and deny SWU upgrade on that basis (they love pulling stunts like that, don't get me started on it!).
If they're saying that she can only upgrade LAX-SYD and not DEN-LAX-SYD that's an obvious error.
Incidently I had a really lovely chatty and friendly agent at SYDRR today who was a delight to talk to and deal with.
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RichardMEL, UA 1K
A Star Alliance Member.