of the Internal Revenue Service or the Office of Chief Counsel may, on behalf of the Secretary, question a witness under oath whose testimony was obtained pursuant to this section. . (b) Effective date (1) In general Except as provided in paragraph (2), the amendment made by this section shall take effect on the date of the enactment of this Act. (2) Application to contracts in effect The amendment made by this section shall apply to any contract in effect under section 6103(n) of the Internal Revenue Code of 1986, pursuant to temporary Treasury Regulation section 301.7602–1T proposed in Internal Revenue Bulletin 2014–28, Treasury Regulation section 301.7602–1(b)(3), or any similar or successor regulation, that is in effect on the date of the enactment of this Act. IV Organizational modernization 11401. Modification of title of Commissioner of Internal Revenue and related officials (a) In general Section 7803(a)(1)(A) is amended by striking Commissioner of Internal Revenue and inserting Administrator of the Internal Revenue Service . (b) Conforming amendments related to section 7803 (1) Subsections (a)(1)(B), (a)(1)(C), (b)(3), (c)(1)(B)(i), and (c)(1)(B)(ii) of section 7803 are each amended by striking Commissioner of Internal Revenue and inserting Administrator of the Internal Revenue Service . (2) Section 7803(b)(2)(A) is amended by striking Commissioner’s and inserting Administrator’s . (3) Subsections (a)(1)(D), (a)(1)(E), (a)(2), (a)(3), (a)(4), (b)(2)(A), (b)(2)(D), (b)(3), (c)(2)(B)(iii), (c)(2)(C)(iv), and (c)(3) of section 7803, as amended by the preceding paragraphs of this subsection, are amended by striking Commissioner each place it appears therein and inserting Administrator . (4) The heading of section 7803 is amended by striking Commissioner of Internal Revenue and inserting Administrator of the Internal Revenue Service . (5) The heading of section 7803(a) is amended by striking Commissioner of Internal Revenue and inserting Administrator of the Internal Revenue Service . (6) The heading of