F visa extension, how?

Hey,

I have a friend from Romania, who have been studying in Denmark for her Master degree in Tourism and Hospitality. She has an agreement with a five-star hotel in Guangdong for doing 6-month research work on customer relation management, and meant to apply for a F for 6 months, but the Danish CVASC only granted her a 3-month duration, single entry.

Now she is in China, and need to extend her F soon. How can she extend her F, where should her supply her application? What is her chance for success?

Thanks, Anne Zhao from Denmark