I'm transiting through BCIA for 5 hours from USA to Manila in Beijing. Luggage question:

I'm flying from Dulles, Wash. DC through BCIA en route to Manila, with about a 5-hour layover between flights. Arriving on United Airlines flight and departing on Air China flight. Do I have to do anything about my checked suitcase or will it automatically be placed on the Air China aircraft? When I leave the USA I'm going to request my suitcase be checked through to Manila. Will this work OK?