; and (2) if the Secretary concurs with the determination of the Federal entity, submit to the President and the Commission a report identifying for reallocation the frequencies with respect to which the Federal entity made the determination. (b) Clearing of spectrum The President shall— (1) not later than 180 days after the Secretary submits a report under subsection (a)(2), begin the process of withdrawing or modifying the assignment to a Federal Government station of the frequencies identified in such report; and (2) not later than 30 days after completing the withdrawal or modification, notify the Commission that the withdrawal or modification is complete. (c) Reallocation and auction (1) In general The Commission shall— (A) reallocate the frequencies identified in a report under subsection (a)(2) for non-Federal use or shared Federal and non-Federal use, or a combination thereof