I have just voted to leave a question open. Then I have read it again and I have realised that no, I think it is off-topic, so I searched here for a button to undo my previous vote; I also checked in the Help Center for an undo action. As I could not find one, I just voted to close the question.
Apparently, the consequence of my double action seems to be that there is one more user that would close the question AND one more user that would leave it open. Is it so and, if so, does it makes sense? Shouldn't I be able to undo my previous vote and then vote to close?