Hi again, more newbie questions from me


I'm due to fly back to the US (DEN) from SYD mid July.

Circumstance (work) has just demanded I be in DUB about 2-3 days after I arrive back to DEN

I figure if I'm going to travel, I may as well forget stopping in DEN and go straight to DUB in one go and recover from jetlag there.

So I'm wondering, will United reservations allow me change my itinerary and purchase and add-on flights or will I need to set up a new one originating in SFO and just miss my SFO-DEN connection? The aternative is to finish my SYD-DEN itinerary and get the 8.07 DEN-LHR flight. Much of a muchness in price but I think I'd rather spend the time on a plane than in the DEN RCC.

The other question is if I'm traveling to DUB, I'm more than likely going to be connecting to LHR or FRA from SFO, will I need to clear US immigration? I arrive in at 11am although my SFO-LHR connection would be at 13.09, volcano permitting so I should be fine.

Of course, I could just go the other direction to DUB over Asia but I thought I'd probably lose my SYD-DEN ticket value and wouldn't earn those EQMs.

Maybe I'm assuming to much but I hoped the flyertalk sages may have an angle that I'm missing from my plans!