Originally Posted by MKE-MR
...As for why UA has the flight as sold out while SQ has it as wide open, I'll leave that battle for somebody else to fight...
That is not unusual and mostly intentional. If you have KVS Availability Tool, you could see that availability for the same flight varies by GDS, or varies by inquiry location within the same GDS.
Originally Posted by MKE-MR
I cannot, unfortunately, SEE anywhere that the SQ reservation is valid because UA's computers do not pick up an SQ segment changed in isolation, by another system. And since it wasn't booked online, I can't see it by logging into my KF account, either. I'll just have to reconfirm a few days beforehand that all is well....
You could ask SQ reservation to email or fax you a confirmation. If you have your KF number in the PNR, you could also use internet check-in to view it. Just log into your KF account, then try to do an internet check-in. It should show you the PNR but won't let you check in until within 48 hours.