___
___ 'n desu ga
Quoted from a Japanese teacher comment on the Net
'n desu ga is often used when you go up to a counter and ask for something.
At an airline counter you could say yoyaku shitai'n desu ga I'd like to make a reservation...
At a hotel counter chekku in shitai'n desu ga I'd like to check in ...
It's really common to say, hear, and use this grammar point in this sort of context.