Hey, I have a big trip tomorrow where I'm traveling with 4 other people in the same reservation. I didn't split it off for upgrade purposes because I wanted to sit with them on the way there (IAH-SAP), but for the return trip I just decided today I would be ok with sitting up front (if I get the upgrade). (I should have just split it earlier, but now I'm hesitant to do so).

We're in the 24-hour window, though technically I don't think we've checked in even though I tried (because of having to show passports).

So:

• Could I do a split after we check in at the customer service desk?
• Would it mess up their baggage/elite benefits?
• Does the PNR change after the split?
• Would it mess up their tickets in general?

Thanks for answering!