Originally Posted by
SK AAR
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To avoid your doubts and any issues, I suggest you book with TK rather than UA. Why do you want to book ORD-ISD-ADD with UA? - when UA is not operating any of the flights. Do yourself a favor and book with the carrier your are flying with. It will also be much easier in case you have schedule changes or cancellations to your flights.
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OP’s ticket is an award ticket. UA doesn’t sell revenue tickets by TK.