Before obligating any resources for voluntary separation incentive payments, the head of each agency shall submit to the Office of Personnel Management a plan outlining the intended use of such incentive payments and a proposed organizational chart for the agency once such incentive payments have been completed.
(b) The plan of an agency under subsection (a) shall include—
a description of which categories of employees will be offered incentives;
a description of how the agency will operate without the eliminated positions and functions.
The Director of the Office of Personnel Management shall review each agency’s plan an  may make any appropriate modifications in the plan, in consultation with the Director of the Office of Management and Budget. A plan under this section may not be implemented without the approval of the Directive  of the Office of Personnel Management.