Conversion from S1 beijing visa to X1 visa in beijing

Hello all, I am a student in Beijing on X1 and my wife was staying with me on long-term dependent (S1). Now she also got admission into master and requires X1. My question is whether she can change/transfer here from S1 to X1. If yes, please advice. I heard from one of my seniors that there are some provisions for changing one visa to another here without going back to my home country, which is Pakistan in my case. If there are any other possible link or articles, kindly let me know.