Rectification of mistake allows amendment of tax intimations within one year, with hearing if liability increases. Rectification under Section 169 allows the Assessing Officer to amend an intimation under the equalisation levy regime to correct apparent mistakes within one year of the relevant financial year's end, either suo motu or on notice from the assessee or e commerce operator; any amendment increasing liability or reducing a refund requires prior notice and a reasonable opportunity of being heard, and if it enhances the sum payable the AO must issue an order specifying the amount and apply the Chapter's provisions accordingly.