It is standard for members’ written resolutions under the Companies Act to be circulated and for there to be a 28 day acceptance period.
As has been pointed out, if a supporting vote is received then it’s irrevocable. Technically speaking, any SPFL club which has voted ‘no’ already can submit a second vote with a ‘yes’. But anyone who votes ‘yes’ can’t retract it or change it to ‘no’.
It is actually pretty unusual for written resolutions to have the option of voting ‘no’. Usually they are only framed in a positive way, with any person who would not back it (or vote ‘no’) simply not responding. It will be passed as soon as supporting responses are received from 75% of the members (for example). On the other hand it won’t officially fail until the 28 day period lapses.