Arcturus | Al
I don't know any of the Potters back home. Not personally, at any rate. I think there's a young one in Gryffindor but my friends and I don't speak to any of that set much. My father probably knows some of your relatives, though. May I ask which year you arrived from?
If you don't care for formality, I might call you just Potter, as if you were a friend from home?