Except as provided in Section 4.39.803, the Council may at any time amend this plan and trust in whole or in part. No amendment shall operate retroactively in such a manner as to deprive any participant of rights, which have vested in such participant prior to the enactment of the amendment or diminish the amount thereof, unless such amendment is required in order to qualify this plan and trust under Sections 401 and 501 of the Code. No amendment shall cause or permit any part of the trust to revert to or become the property of the employer or to be used for or diverted to any purpose other than the exclusive benefit of participants, former participants or their beneficiaries. No amendment substantially increasing the obligations or the liabilities of the trustee shall be made without the trustee’s written consent. (Ord. 6837-NS § 1 (part), 2005)