47 U.S.C. § 924: Withdrawal or limitation of assignment to Federal Government stations

within 6 months after receipt of a report by the Secretary under subsection (a), (d)(1), or (f) of section 923 of this title , withdraw the assignment to a Federal Government station of any frequency which the report recommends for immediate reallocation; within any such 6-month period, limit the assignment to a Federal Government station of any frequency which the report recommends be made immediately available for mixed use under section 923(b)(2) of this title ; by the delayed effective date recommended by the Secretary under section 923(e) of this title (except as provided in subsection (b)(4) of this section), withdraw or limit the assignment to a Federal Government station of any frequency which the report recommends be reallocated or made available for mixed use on such delayed effective date; assign or reassign other frequencies to Federal Government stations as necessary to adjust to such withdrawal or limitation of assignments; and transmit a notice and description to the Commission and each House of Congress of the actions taken under this subsection. may substitute an alternative frequency or frequencies for the frequency that is subject to such determination and withdraw (or limit) the assignment of that alternative frequency in the manner required by subsection (a); and shall submit a statement of the reasons for taking the action described in subparagraph (A) to the Commission, Committee on Energy and Commerce of the House of Representatives, and the Committee on Commerce, Science, and Transportation of the Senate. the reassignment would seriously jeopardize the national defense interests of the United States; the frequency proposed for reassignment is uniquely suited to meeting important governmental needs; the reassignment would seriously jeopardize public health or safety; the reassignment will result in costs to the Federal Government that are excessive in relation to the benefits that may be obtained from commercial or other non-Federal uses of the reassigned frequency; or the reassignment will disrupt the existing use of a Federal Government band of frequencies by amateur radio licensees. For purposes of paragraph (1), a frequency may not be substituted for a frequency identified and recommended by the report of the Secretary under section 923(a) of this title unless the substituted frequency also meets each of the criteria specified by section 923(a) of this title . withdraw or limit the assignment to Federal Government stations on a later date that is consistent with such plan, except that the President shall notify each committee specified in paragraph (1)(B) and the Commission of the reason that withdrawal or limitation at a later date is required; or substitute alternative frequencies pursuant to the provisions of this subsection.