i have S1 .now is it possible to change x1 without back to home

sadia, it's possible to convert your current S1 type to a work Z type at the exit and entry administration of the local PSB within China. 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 Chinese residence permit, admission letter and JW form from the school as well as the physical examination record.