Christos Earnest! Christ is Risen!
so lets say that almost all orthodox bishops want to reunite with the west as voted in a unorthodox council but there is a lone bishop that refuses, what happens next?
Been there, done that

. Ask Saint Mark of Ephesus.
John.
St. Mark is my patron.
If one Bishop refuses the impact depends upon who that Bishop is. Without Mark, the false union had no hope. But the process includes how the people accept or reject such agreements. Back then, it was St. Mark plus the rejection of the mass of Othodox people that did in the false union.
So it will be with us today.
Mark