47 U.S. Code § 924. Withdrawal or limitation of assignment to Federal Government stations
(a) In generalThe President shall—
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.
(1) Authority to substituteIf the President determines that a circumstance described in paragraph (2) exists, the President—
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.
(2) Grounds for substitutionFor purposes of paragraph (1), the following circumstances are described in this paragraph:
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 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
(3) Criteria for substituted frequencies
(4) Delays in implementationIf the President determines that any action cannot be completed by the delayed effective date recommended by the Secretary pursuant to section 923(e) of this title, or that such an action by such date would result in a frequency being unused as a consequence of the Commission’s plan under section 925 of this title, the President may—