This question may not be specific to USDM but here goes:
I have the first half of a SYD-xNRT-GUM trip that I want to change. It was booked under USDM rules (30k J) when the outbound seats opened but not the inbound. I thought I would have had time in April to add the return segments but it didn't work out. Long story short, I want to change the SYD-xNRT-GUM to a date a few months later (allowed), and use that as a positioning flight to the US (prob NRT-LAX) under a separate ticket. ie. get to HND and no-show the NRT-GUM.
So if I book a separate NRT-LAX, departing on the same day of arrival into HND, will the system "see" that I have an impossible connection (to/from GUM) and cancel the ticket to LAX?
SYD-HND is QF25: 2130-0530(+1),
NRT-GUM is JL941: 1045-1525 and
NRT-LAX is JL62: 1705-0950
In theory I wouldn't be able to get back to NRT in time for the LAX flight (the GUM-NRT is JL 942: 1655-1940).
I haven't pushed back my SYD-xNRT-GUM flight yet (but can do so for free with AA rules), but my provisional plan is to get them to cancel the NRT-GUM with no penalty (wishful thinking). To avoid the "risk" of them cancelling the NRT-LAX ticket. But then again if the SYD-xNRT-GUM is revalidated on USDM ticket stock and I have a new NRT-LAX on AA ticket stock, maybe the systems won't recognise each other?
My rationale in a very roundabout way is:
South Pacific to Asia 2 (GUM) is not allowed via Asia 1 (HND/NRT) so they have to drop the last segment!
As an aside I thought I'd be able to go NRT-xHKG-LAX to go on CX F but alas, no backtracking. JL F it may have to be.