(1) The Director of Lands and Buildings Tax, the Deputy Director of Lands and Buildings Tax, the Assistant Director of Lands and Buildings Tax, the Lands and Buildings Tax Officer, the appellate authority or the Revising Authority may at any time within three years from the date of any order passed by him or it, rectify any error apparent on the face of the record: Provided that no such rectification which has the effect of increasing the assessment shall be made unless such authority has given notice to the assessee and has allowed him a reasonable opportunity of being heard. (2)Where such rectification has the effect of reducing the assessment, the amount due to the assessee shall be refunded to him. (3)Where any such rectification has the effect of increasing the assessment already made, the assessing authority shall give the assessee a revised notice of demand and thereupon the provisions of this Act and the rules made thereunder shall apply as if such notice has been given in the first instance.