Dragonair management in general are quite welcoming of prospective pilots coming to have a look a round and to make themselves known. It indicates a serious application and a desire to find out firsthand what you are getting into and of course, they get to have a look at you. It would be best to ring first and ensure that the people you work for are actually going to be their and have the time to see you. Try ringing +852 3193 3193 (switchboard) and asking for the Assistant General Manager - Operations or the Manager - Crew Resources. They should be able to help you out.
Good luck
