I think that it depends on what you're reason is for rescinding you're vote,
if some1 is verry friendly, you vote yes and than he starts to yell at you i think that you may rescind you're vote then
opinions will differ, but if you got vote for a politician or something, you cant later go back and change it, i think it would just make things simpler if you only had one vote. make up your mind and vote, if your minds not made up, then dont vote yet. Thats another reason i think this thread should be closed and another one started in time when toga thinks he may have garnered more votes.