Originally Posted by GinFizz

As moondog notes, this is absolutely fine. In the past I have credited all my domestic Air China flights to SAS (SK) without any issues whatsoever.

I suggest to download the Air China app and then 48 hrs before your flight you can try and check-in using your passport number, flight number and name. The name part might trip up the system - it will need to be the same as used for the booking (e.g. LAST FIRST, or FIRST LAST, or LAST MIDDLE FIRST, etc.). Definitely all capitals needed. Spaces seem to work fine these days (many years ago we had to use LAST/FIRSTMR (as an example) to get things to work). If you can find your flight that way you should be able to add your FF number. And if not just showing your card (or the FF number - help them by adding the "UA" part) at check-in should be absolutely fine.

Welcome also to China! Where is your final destination?