(a) The pension board shall have the right at any time to amend the plan, subject to the limitations of this section. Any amendment shall be consistent with the act, any other legislation relating to the system, or consistent with other authority granted to the pension board. Additionally, in the event that the Legislature amends the act or makes other statutory changes that impact the terms of the plan, the pension board shall cause the plan to be amended as necessary to reflect such legislation. The pension board, and each of its individual members, when acting in its or their official capacity, shall be immune from civil liability against the claims of any individual, member, or other entity of any nature whatsoever arising out of the pension board's or its members' administration of the plan or related to its decisions or actions, which decisions or actions were made in good faith, without malice, and predicated upon information that was then available to the pension board.

(b) As determined by the pension board or by legislative act, any change in the pension rate may apply to all pensions payable under the plan, including pensions granted prior to the effective date of the change in the pension rate. This subsection shall apply whether such change results in the pension benefit being increased or decreased. Accordingly, any increase or decrease in the pension rate may be applicable not only to persons who have not yet begun to receive their pension benefits, but also to persons who have begun receiving their pensions benefits. A change in the pension rate means any modification to the definition of basic average salary or other change to the formula for determining the amount of a pension benefit.

(c) Any amendment which affects the rights, duties, or responsibilities of the trustee may only be made with the trustee’s written consent. Any such amendment shall become effective as provided therein upon its execution. The trustee shall not be required to execute any such amendment unless the amendment affects the duties of the trustee hereunder.

(d) Except as otherwise specifically provided for herein, no amendment to the plan shall be effective if it authorizes or permits any part of the trust fund, other than such part as is required to pay taxes and administration expenses, to be used for or diverted to any purpose other than for the exclusive benefit of the members or their beneficiaries or estates.