According to Article 42 of the Detailed Rules for the Implementation of the Patent Law:
Where an application for a patent includes two or more inventions, utility models or designs, the applicant may file a divisional application. The divisional application shall not change the category of the original application.
According to Article 5 1 of the Detailed Rules for the Implementation of the Patent Law:
The applicant for a patent for invention may, within 3 months from the date of receiving the notice that the application for a patent for invention has entered the substantive examination stage issued by the patent administration department of the State Council, take the initiative to propose amendments to the application for a patent for invention.
An applicant for a patent for utility model or design may, within 2 months from the date of application, put forward amendments to the application for a patent for utility model or design.