Possible to change a newly issued Student visa to a Z working visa?

Hey all I am wondering if anyone in Beijing knows if it is possible and legal to change an extended student visa in to a z working visa? (I've already graduated, but have chosen to extend my student visa longer for further 1 year studies) Reason being, I found a full time job in Beijing but made the money wasting mistake of extending my visa in China for 1 more year for language courses. Now that the company agrees to hire me on a z visa, (they will not take me as a student) is it still possible to change the newly issued student visa to a working visa and STILL attend classes? Considering i've already payed the tuition and my name already appears on the school system I think, my visa will only be the one that changed. Thanks