1. (1) it is demonstrated that there was an intent on the part of the employing agency to hire the retiree pursuant to section 211 of the Retirement and Social Security Law;
2. (2) the retiree understood that he was being employed pursuant to that section; and

3. (3) only through an error of commission or omission approval was not effectuated.

   The burden to demonstrate such exception circumstances is upon the employing agency.

Approval of the employment of a retiree pursuant to section 211 of the Retirement and Social Security Law must be secured prior to the effective date of that employment; provided, however, the commission may under the following exceptional circumstances grant such approval retroactively where: