Concurrent exercise of assessment powers: authorisation for assessing officers to issue intimations, refunds and rectifications. Authorisation empowers senior tax officials to issue written orders permitting Assessing Officers to exercise powers and perform functions concurrently in relation to issuance of intimation and refund and the rectification of such intimation under the Income-tax Act, enabling subordinate Assessing Officers to act jointly or interchangeably with other Assessing Officers.