The model standing order states:
7. Previous resolutions
a) A resolution shall not be reversed within six months except either by a special motion, which requires written notice by at least ( ) councillors to be given to the Proper Officer in accordance with standing order 9, or by a motion moved in pursuance of the recommendation of a committee or a sub-committee.
From my experience, 3 is the number most commonly used here, although others may have different views.
Worth noting that a committee or sub-committee may recommend a motion, which would require only a simple majority of those present at a quorate meeting of that committee.