6. Amendment of certificate of enrollment.-
(1) The certificate of enrollment granted under rule 4 shall remain valid so long as it is not cancelled under sub-rule (2) of rule 7.
(2) An application for a revised certificate of enrollment shall be made in Form II. On receipt of such application the prescribed authority may call upon the applicant to furnish such additional information or evidence as may be necessary for determining the amount of tax payable by him according to Schedule I to the Act and after so determining the amount of tax payable by the applicant, the prescribed authority shall make necessary amendment in the certificate of enrollment under his dated signature, indicating the year from which the tax at the revised rate shall be payable.
(3) The provisions contained in sub-rule (2) of rule 5 shall mutatis mutandis apply to the amendments to the certificate of enrollment