The police have my passport to process my residency permit! How can I book flight?

I would like to book a flight to Beijing for a few days, or if I can't do that, spend a few days in Xian. I have been told I can travel with only a photocopy (!) of my passport and visa documents. IS THIS TRUE? I don't want to spend money on travel tickets or booking a hotel only to be told I can't board the train/plane.