GuangZhou is the only place I have changed money in China..I have done in the Garden Hotel..You have to show them your passport and I think they make a copy..The will only change up to $200 USD..The Landmark Hotel does not want to exchange money..They tell you to go to the bank in the next building..There are 2 banks there...one ask you to fill out a form and look at your passport...but the other wants you to make a Xerox copy of your passport for them..I had no problem with either one..There are lady outside the street ask for changing money..but I never did it with them