Is the flight from South Korea to Hong Kong goes through Shanghai and requires me to change airport in shanghai?what kind would i require?

Roy, do you mean that you fly from Macau to Shanghai and then fly back to Canada? From which airport will your flight take off for your return trip? Some of the flights from Macau to Shanghai land at Hongqiao Airport and some others land at Pudong Airport. You may choose a flight that lands at the same airport where your return flight takes off.

The flight from Irkutsk to Sydney involves a short layover in Beijing, and arrives into Shanghai's Hongqiao Airport, followed by a change of airport required from Hongqiao to Pudong. The flight from Shanghai Pudong Airport is after a 12 hour layover. Is the passenger allowed to walk out of Hongqiao Airport under the 72 hr free policy? or is it necessary to have a China Tourist L just to get out of Hongqiao Airport to catch the next flight from Pudong?

Yes. I will have to travel back to shanghai from Macao and then head back to calgary. I have a round trip ticket booked for calgary to shanghai and back. But in that time frame I will leave china and go to korea. However on my way to honk kong and Macau, my flight transfers through shanghai and requires me change airports and I only have 8 hours to do so. Sort of makes it that I have to enter thrice.

Basically yes. I have a round trip ticket booked for Calgary to shanghai and back. But I am heading to japan in the middle as well. And then heading to honk kong and Macau through shanghai, where I land in hongqiao and take off from pudong airport. So for that I have 8 hours and a change of airport in shanghai. And then I have to head back to shanghai from Macau to catch my round trip flight back from shanghai to calgary.

Roy, for a stopover/transit in China for less than 24 hours, visa is not required. So, you need to apply for a double entry Chinese visa in advance for this visit.

Hi Nervous from Australia, because your flight stops in both Beijing and Shanghai, you can not avail this 72 hour free transit. But if the total stopover is within 24 hours, you still enjoy free transit. But you have to apply for a free stay permit after arrival at the airport if you want to go out.