S. 263: Commissioner – Revision of orders prejudicial to revenue – Accommodation entries -Revision under section 263 could not be exercised on the basis of a void reassessment order – Reassessment – Sanction – Jurisdictional condition – Assessment Year 2017-18 – Notice under section 148 issued on 29-07-2022, beyond three years from end of relevant assessment year – Approval obtained from Principal Commissioner under section 151(i), whereas section 151(ii) required approval from Principal Chief Commissioner/Chief Commissioner – Sanction by authority not prescribed under applicable provision was a jurisdictional defect – Reassessment proceedings held void ab initio – Revisionary order quashed. [S. 147, 148, 148A, 151(i), 151(ii), 254 (1) ]