Experience for H4 in China?

Do some folks have experiences to apply H4 visa in China? Any suggestions are much appreciated.

The situation for me is: My wife went back China for an emergency visit and needs the visa stamp to come back. Her current H4 is the first year of three-year H status. In addition to the documents (copyed) I had used for my H1 and her H4 applications, does she need other documents in Chengdu? and what are those?

Thank you very much for your consideration and help.