Here's the situation:

Two flights on the same reservation

Flight on Saturday morning operated by UA
Entered AC number at check-in
AC number printed on boarding pass

Flight on Sunday morning (25 hours 29 minutes later) operated by UA
Entered TK number at check-in
TK number printed on boarding pass

On Tuesday, both flights posted to TK account

Any way to get this corrected to the numbers intended (the numbers printed on the boarding passes)? Who do I contact? UA I assume?

Really appreciate any experience here. I'm afraid that it's so late in the year I need to send my wife on an expensive same day YYT-YHZ-YYT trip just so she can get the 1000 miles she was supposed to get from the first UA flight in order to hit 50k on AC.

Thanks all.

You would need to contact TK first to remove the posting from their files. Then be prepared for a battle to get the credit posted to UA. The records will show that miles have already posted to TK. Take lost of screen shots.

Luckily UA is run by real humans who will try to help you fix this, unlike AC CS who get back to you in 6-8 weeks with a "not possible" answer.