Originally Posted by jiejie

Your journey qualifies for Transit Without Visa in both directions. Assuming you are Canadian (or passport from one of the other 50+ approved countries), you don't need to get a visa. You don't need to change your ticketing or your airports. SHA and PVG are essentially considered interchangeable for TWOV purposes and you can use them in any combination as long as the time limit in Shanghai is met. You may now stop listening to the contradictory clowns in Toronto, neither of which seems to know the actual regulations.