(a) All public assistance grants made under this article shall be reconsidered by the county departments of family and children services as frequently as may be required by rules of the Board of Human Services; but in every case the county department shall make such reconsideration at least once each year. After such further investigation as the commissioner may deem necessary, the amount of public assistance may be changed or may be entirely withdrawn if it is found by the department that any such grant has been made erroneously or if it is found that the recipient's circumstances have altered sufficiently to warrant such action.

(b) If, at any time during the continuance of public assistance, the recipient thereof becomes possessed of income or resources in excess of the amount previously reported by him or if other changes shall occur in the circumstances previously reported by him which would alter either his need or his eligibility, it shall be his duty to notify the county department of such fact immediately on the receipt or possession of such additional income or resources or on the change of circumstances.

(c) The department may also, upon its own motion, review any decision of a county department and may consider any application upon which a decision has not been made by the county department within a reasonable time. Where the department, on its own motion, reviews a decision of a county department or considers applications upon which a decision has not been made, it may make such additional investigation as it may deem necessary; and it shall determine whether the applicant shall be granted assistance and the amount of such assistance and whether assistance being paid to a recipient shall be modified or canceled. Any applicant or recipient affected by such a decision of the department shall, upon request, be given reasonable notice and opportunity for a hearing by the department.