(1) If the patent application fee has not been paid, resubmit a new application directly, using you and Zhang San as the applicants, and claim the priority of this patent, so as not to lose the filing date. No need to pay more. Previous cases will be withdrawn directly because domestic priority is claimed.
(2) If the application fee has been paid, you need to submit it by changing the bibliographic item, and at the same time, you need to submit an agreement from the original applicant (that is, you) to add Zhang San as the second applicant. supporting documents, and then pay a supplementary fee of 200 yuan for the change of bibliographic items.