。
I'm a traveler, and I'd like to see a doctor.
Literal
Traveler is [but-が] examination [object-を] request want [explanatory-のですが].
旅行者ですが introduces the speaker's situation before making a request — the が softens the transition. 診察をお願いしたいのですが layers politeness: お願いしたい (want to request) + のですが (explanatory + trailing but). A practical sentence for medical emergencies abroad.