Extension of notification date under GST law preserves existing state tax rate applicability for an additional three-month period. Amendment under section 11(1) of the Gujarat GST Act substitutes the previously specified calendar date in an earlier state tax rate notification with a later date, thereby extending the period during which the notification's state tax rate provisions remain operative; the change is effected by substituting the figures, letters and words denoting the earlier date with those denoting the later date and is promulgated in the name of the Governor.