Can the patent application documents be modified?

Of course. The Patent Law clearly stipulates that an applicant may modify his patent application documents, but the modification of the application documents for patents for inventions and utility models shall not exceed the scope recorded in the original specifications and claims, and the modification of the application documents for patents for designs shall not exceed the scope indicated in the original pictures or photographs.

Legal basis:

Article 33 of the Patent Law of People's Republic of China (PRC) * * * An applicant may modify his patent application documents, but the modification of the application documents for patents for inventions and utility models shall not exceed the scope recorded in the original specification and claims, and the modification of the application documents for patents for designs shall not exceed the scope shown in the original pictures or photographs.