how to leave China after getting COPR ???? please help !!!!

[Dko]

hello all
my wife from Guangzhou China finally got the COPR and the Canadian visa stamped on her Chinese passport, we will be flying to Edmonton at the end of Sept.
I was wondering if she need to get a exit-permit from the local Public Security Bureau in order to leave China? Or does she just need her Chinese passport, the COPR letter and the one way air ticket to Edmonton?

please help thanks