I am currently working in China (Qinhuangdao) as a college teacher, with a Residence Permit.

I am interested in changing jobs to a small, private school. They can get me a z visa,Residence Permit. But I need to know the procedures for changing jobs. The school I am at now must agree to 'release' me, correct? Once they do that, then the new school can start and complete the new Residence Permit application. Is this all correct? What if the college agrees to release me, but then the new procedure doesn't work out (does that make sense?)
Thank you for your help.