Hi everyone!

I'm in Lisbon on holiday with some friends and we are flying home tonight. Unfortunately somehow my sister's online check in got messed up through TAP Portugal's app and she checked in with wrong nationality and passport details. Coming here she flew with her national ID card and we had no problems. Now when we checked her boarding pass in the app, at details it shows her nationality as United Kingdom(we are Hungarians), she checked in with a British passport with passport numbers 11010110. We tried to cancel the check in for her to redo but we still can't change these details. I know that the easiest option would be to just go to the airport and ask them if they could fix it but we are a bit worried that it would cost a lot or we'd have to buy a new ticket for her. Has anyone been in a similar situation? What do you think, how should we proceed? Thanks for any advice.