Within sixty days of the adoption and promulgation of the standards for certification by the Department of Health and Human Services, each area agency on aging shall submit to the department for approval a plan of operation to either provide and supervise or subcontract for at least one certified care management unit to provide all eligible individuals residing in its planning-and-service area with long-term care management services. Within thirty days of receipt of a plan for approval, the department shall notify the area agency on aging of its acceptance or denial of the plan. If the plan is denied, the department shall give the reasons for denial and the area agency on aging shall submit a revised plan. If the area agency on aging does not submit a revised plan within thirty days of the denial, the Department of Health and Human Services may contract with another public or private entity to serve that planning-and-service area.