Standby Upgrade to F at T-6 for LAX-DFW leg of SYD-LAX-DFW flights possible?
 

My sister is traveling from SYD-LAX-DFW on Virgin Australia and Virgin America respectively. I'm based in the US.

Is it possible for me to upgrade her at T-6, given that she is already in the air on her SYD-LAX flight? Some questions?

1. Do I just revoke her prior check in for LAX-DFW?
2. Any issues with revoking her check in if her bags are checked through from SYD to DFW?
3. Should she just not check in for her LAX-DFW flights, and only have her bags checked through to LAX?
4. What am I missing?

TIA.

I think your sis sis better off asking when she checks in for advice if either one of you don't call in before her flight. But then again, if she doesn't check in all the way through to DFW, maybe there is a chance that that a non middle seat will still be available in MC or even MCS if no F seats are available upon arrival and check-in at LAX.

Best of Luck!

Cheers!