In a few weeks I値l be taking a return flight to a Schengen country where I知 living for more than the 90-day tourist period. I hold a US passport and I have I have an unusual (but valid) set of entry documents for the country. I知 100% sure that I will be able to enter the country upon presentation of these documents but I知 concerned about convincing the airport staff of that as I値l need to do in order to get a boarding pass. I'm especially concerned as my trip begins early morning at a regional airport where I壇 expect the staff to not have much experience with this sort of thing. The Travel Ready Center tells me that I値l need to have my documents verified. Is there a United office that I could email copies of the documents to beforehand to get preapproval?