(a) Except as provided by subsection (b), the board of directors shall, from time to time after the adoption of an official plan, have the power to modify, amend or extend the same, provided that upon the making of any such modification, amendment or extension thereof, the board of directors shall cause notice to be given and shall conduct a hearing, all as provided in Kan. Stat. Ann. § 12-3407, and amendments thereto.

(b) The board of directors of a port authority located in Cowley county shall not have the power to modify, amend or extend the same to change or alter the character of the work to be undertaken by the port authority which would allow the use of any land or site acquired through the exercise of eminent domain to be used for a recreational-use purpose, nor to allow private development upon such acquired land or site for a period of 30 years from the date of acquisition of such land or site. The board shall not adopt any modification, amendment, or extension until the notice has been given and the hearing held as therein provided.