During the patent examination process, if the applicant is unable to perform or complete a certain act or procedure within the prescribed time limit due to legitimate reasons, the applicant may request an extension of the time limit. It should be noted that the applicant can only request an extension of the specified time limit and cannot request an extension of the statutory time limit. However, in the invalidation procedure, because the vital interests of the patentee and the infringer are involved, the time limit specified by the Patent Reexamination Board cannot be extended.