The Director, or any person authorized in writing by the Director, is authorized to enter into an agreement in writing with any person relating to the liability of such person (or of another person for whom such person acts) with respect to any tax that is subject to administration and enforcement by the Department of Finance and imposed under the Delaware Code for any taxable period. Such agreement shall be final and conclusive, and, except upon a showing of fraud or malfeasance or misrepresentation of a material fact:
30 Del. C. § 564