(a) 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 for assistance, it shall be the duty of the recipient immediately to notify the county office of the receipt or possession of the property or income. The Department of Human Services may either cancel the assistance or alter the amount thereof in accordance with the circumstances.
(b) Any assistance paid after the recipient has come into the possession of the property or income and in excess of his or her need shall be recoverable by the state as a debt due the state.