Subject to modifications or revocation by authority of the Executive Director, during the continuation of emergency conditions authority to effect temporary appointments of such additional officers and employees, to classify and allocate positions to their proper grades, to issue travel orders, and to effect emergency purchases of supplies, equipment and services shall be exercised by the respective Directors of Offices and officials in charge of regional offices, their deputies, or staff in line of succession, as may be required for the discharge of the lawful duties of such organization.