If at any time during the continuance of assistance the recipient thereof becomes possessed of any property or income in excess of the amount stated in the application, it shall be the duty of the recipient immediately to notify the local unit of the receipt or possession of such property or income and the local unit may, after investigation, either cancel the assistance or alter the amount thereof in accordance with the circumstances. Any assistance paid before the recipient has come into possession of such property or income and in excess of his need shall be recoverable by the county department as a debt due. The net amount realized from all such claims shall be divided between the State and the local subdivision in proportion to the amount of the assistance paid by each respectively. All rights of recovery formerly granted under the provisions of the subtitle known as "Old Age Assistance", §§ 63 through 83 of this article and provisions of the subtitle known as "Public Assistance to the Needy Blind", §§ 11 through 30, of Article 30, shall not be cancelled or diminished and shall remain in full force and effect.