Of course. According to Article 37 of the Labor Contract Law, the employee may terminate the labor contract by giving a written notice to the employer thirty days in advance and three days in advance of the probation period. There is no requirement that employees can resign only after the signature of the leader. But generally don't do this if it's not necessary. This is against workplace etiquette. Article 37 of the Labor Contract Law stipulates as follows:

Article 37 A laborer may terminate the labor contract by giving a written notice to the employing unit 30 days in advance. The employee may terminate the labor contract by notifying the employer three days in advance during the probation period.