Senate. (4) Vacancies A vacancy in the Oversight Board shall be filled in the same manner in which the original appointment was made. (d) Additional authorities (1) Subpoena The Oversight Board may issue subpoenas requiring the attendance and testimony of witnesses and the production of any evidence relating to any matter the Oversight Board is empowered to investigate under subsection (b). The attendance of witnesses and the production of evidence may be required from any place within the United States at any designated place of hearing within the United States. (2) Obtaining official data The Oversight Board may secure directly from the Internal Revenue Service information necessary to enable it to carry out this section. Upon request of the Chairperson of the Oversight Board, the Commissioner of Internal Revenue shall furnish such information to the Oversight Board. (e) Termination The Oversight Board, and its authorities under this section, shall terminate on the expiration of the 15-day period beginning on the date on which the Secretary terminates the Program. 9. Severability If any provision of this Act (or the application of such provision to any person or circumstance) is held invalid, the remainder of this Act (or the application of such provision to other persons or circumstances) shall not be affected. 10. Definitions In this Act: (1) Authorized representative The term authorized representative means an exclusive representative of employees, designated and authorized by the employees without interference, influence, or coercion by an employer of such employees. (2) Corresponding 2019 period The term corresponding 2019 period means, with respect to a month or period of months, that same month or period of months in 2019. (3) Covered employee The term covered employee means an individual— (A) employed by a grant recipient under the Program on a full time, part-time, or other basis