You will need to post somewhere in the China forums. I am not at all familiar with the process they have, if any. Someone there should understand enough English to help you out. I also don't know if anyone else outside of the China editors know what their process is, if any.

If you can't get an answer in the China forums, then go through the "Ask a Question" box on the Support page and click through several times after entering "china area manager" if you don't find your answer. Eventually you'll get to a "Email us" link at the bottom of the pane and you can use this to open a ticket with Waze and request a managed area.