Changing L into M type?

Abby, if you want to convert your current L type into M type within China, that's possible. If it can be done, you don't need to leave China. You should prepare the relevant documents including your passport and its copy, the application form, a passport-style photo, valid registration form of temporary residence, invitation letter from the business partner as well as the physical examination record, the return ticket and other requirements. Then, submit the application to the local PSB.