legal ground
Article 51 of the Detailed Rules for the Implementation of the Patent Law of People's Republic of China (PRC).
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.
Where the applicant modifies the patent application documents after receiving the notice of examination opinions issued by the patent administrative department of the State Council, it shall modify the defects pointed out in the notice.
The patent administration department in the State Council can correct the obvious errors of words and symbols in the patent application documents by itself. Where the administrative department for patent in the State Council modifies it by itself, it shall notify the applicant.