Air Canada has some discount deals from Delta hub cities to Hong Kong for $435 roundtrip. Fares at this price are available from Atlanta (ATL), Detroit (DTW), and Minneapolis (MSP).
Flights are available daily starting in the middle of January through early April, which would be a good time for an escape from the Michigan and Minnesota winters. A Saturday night stay is required, and on some itineraries, there might be a long layover or overnight required, those are mostly for the Minneapolis departures.
As an example, searching on Orbitz, I found tickets departing DTW on Tuesday, January 22 and returning from HKG on Monday, February 11, 2019. It is best to book through a third-party site, like Priceline or Orbitz as their prices are about $25 less than what the Air Canada site is offering. But if you feel more comfortable booking directly with the airline, it will cost $461 for most dates.
This is the last day of Air Canada's Fall Sale, so if you are interested in these fares, I recommend you book them ASAP as they probably won't be around tomorrow at this price. If you are on the fence, the third-party sites I listed above will allow for free cancelations within 24-hours, so you can purchase now and cancel tomorrow if you change your mind.
If you need a place to stay in Hong Kong, we've got you covered with a long list of options provided by Hotelwatchdog.