You can refer to the lawyer law:
Article 31 When acting as a defender, a lawyer shall, according to the facts and laws, put forward materials and opinions on acquittal, lighter punishment or reduction or exemption of criminal responsibility of criminal suspects and defendants, and safeguard the legitimate rights and interests of criminal suspects and defendants.
Article 32 A client may refuse his entrusted lawyer to continue to defend or represent him, and at the same time, he may entrust another lawyer to act as a defender or agent.
After accepting the entrustment, a lawyer shall not refuse to defend or represent without justifiable reasons. However, if the entrusted matter is illegal, the client uses the services provided by the lawyer to engage in illegal activities, or the client deliberately conceals important facts related to the case, the lawyer has the right to refuse to defend or represent him.