What are the conditions for being an agent in criminal proceedings?

According to the provisions of the Criminal Procedure Law, the following persons can act as agents in criminal proceedings: (1) lawyers; (2) A person recommended by a people's organization or the unit to which the criminal suspect or defendant belongs; (3) Guardians, relatives and friends of criminal suspects and defendants. Article 33 of the Criminal Procedure Law of People's Republic of China (PRC) and Article 47 of the Criminal Procedure Law of People's Republic of China (PRC).