As I know ,it is very diffecult for visa agents to convert L or F visa to working visa without leaving China now ,especially for Filiino and South- East countries nationalities.
But someone said they are able to help uropean countries ,especially for Filiino and South- East countries nationalities to process working visa without leaving China for 7 working days with simple documents . Do you believe it ? Did you ever use her service ,a lady ,named Cindy , phone number is 13366058066?