Earlier I answered a question, and somebody offered a completely different answer which (upon my understanding of the original question) was invalid. Because this answer wouldn't work, I down voted it.
However, the Original Poster then edited the question and offered some more information, at this revelation, my solution became invalid and the other answer became valid. I tried to then take my down-vote away (because I was admittedly wrong) but unfortunately, I was unable to do so. Now this user has suffered a reputation decline because I misunderstood the OP.
Why can't we remove down-votes?