Okla. Stat. tit. 18, § 441-404
(b) If a proposed amendment to the organic rules would affect members in two or more districts or classes entitled to vote separately under subsection (a) of this section in the same or a substantially similar way, the districts or classes affected must vote as a single voting group unless the organic rules otherwise provide for separate voting.
Historical Data Laws 2009, HB 2148, c. 68, § 36, eff. January 1, 2010.