Article 51 of the "Implementing Rules for the Patent Law of the People's Republic of China"
1. When an applicant for an invention patent submits a request for substantive examination and when receiving a patent application from the State Council, Within 3 months from the date of the notice issued by the administrative department that the invention patent application has entered the substantive examination stage, the invention patent application can be modified on its own initiative.
2. Applicants for utility model or design patents may proactively propose modifications to their utility model or design patent applications within 2 months from the filing date.
3. If the applicant makes modifications to the patent application documents after receiving the notice of examination opinions issued by the Patent Administration Department of the State Council, the applicant shall make modifications to address the defects pointed out in the notice.
4. The patent administration department of the State Council can correct obvious errors in words and symbols in patent application documents on its own. If the patent administration department of the State Council makes modifications on its own initiative, it shall notify the applicant.