Patents Act, 1970
(1) Subject to the provisions of section 59, the Controller may, upon application made under this section in the prescribed manner by an applicant for a patent or by a patentee, allow the application for the patent or the complete specification to be amended subject to such conditions, if any, as the Controller thinks fit:
PROVIDED that the Controller shall not pass any order allowing or refusing an application to amend an application for a patent or a specification under this section while any suit before a court for the infringement of the patent or any proceeding before the High Court for the revocation of the patent is pending, whether the suit or proceeding commenced before or after the filing of the application to amend.
(2) Every application for leave to amend an application for a patent or a specification under this section shall state the nature of the proposed amendment, and shall give full particulars of the reasons for which the application is made.
(3) Every application for leave to amend an application for a patent or a specification under this section made after the acceptance of the complete specification and the nature of the proposed amendment shall be advertised in the prescribed manner.
(4) Where an application is advertised under sub-section (3), any person interested may, within the prescribed period after the advertisement thereof, give notice to the Controller of opposition thereto; and where such a notice is given within the period aforesaid, the Controller shall notify the person by whom the application under this section is made and shall give to the person and to the opponent an opportunity to be heard before he decides the case.
(5) An amendment under this section of a complete specification may be, or include, an amendment of the priority date of a claim.
(6) The provisions of this section shall be without prejudice to the right of an applicant for a patent to amend his specification to comply with the directions of the Controller issued before the acceptance of the complete specification or in the course of proceedings in opposition to the grant of a patent.