In China, after a patent application for invention is filed, the applicant has only two chances to voluntarily amend its patent application: one is at the time of requesting substantive examination, and the other is within three months from receipt of the Notification of Entry into Substantive Examination.  But any voluntary amendment shall not go beyond the scope of original disclosure of the application.  When responding to the office actions during substantive examination, amendments to the application shall be limited to the amendments for overcoming the defects pointed out in the rejections or objections of office actions.    

For a patent for utility model or patent for design application, the deadline for making voluntary amendment is within two months from the Chinese filing date.