They might be able to avoid having the SPFL clubs vote on it and do it through the league's board if there is no modification to the "prize money" distribution shares but the Club 42 playoff rules are a legally binding agreement between the SPFL, SFA, HL and LL so there is no way to insert a new league entity into those proceedings without all four of those bodies signing off on the changes. It's like what happened with the SJFA entering the pyramid intact. The SFA board wanted it to happen and were firing off directives about it, but all of the SFA, LL, EoS and SoS had to sign off on the playoff rule changes required to make it possible.