What should the foreign expert pay attention to when leaving China ?

When leaving China after expiration of engagement, the foreign experts, scholars and their family members may present their valid passport and valid residence certificate in China for exit. At the time of exiting, they shall present their residence certificate to the border inspection office for cancellation. Where they leave and are to reenter China within the term of validity of their residence, they shall, before leaving, apply to the local public security organ for reentry visas and present their residence certificate to the border inspection office at the time of exit.

Source:http://www.networkesl.com/english/web/48_69_84.html