I'm not having any luck with managing my trip on the Turkish Airlines app. I have an award flight booked with United, I went to the app and put in my eticket number from the email from United and surname. It then takes me to an Add Passenger tab where it asks for Surname and ticket number again. I tried putting in the eticket number of the other passenger here (same surname) and click add passenger, and it gives me an error that says "Passenger could not be found", any tips on this error and how to get past it? Thanks.