I am a bit new to the world of reputation management, and have worked ranking up YouTube videos. But in the case of this client there is a very negative comment on YouTube. They are afraid to flag the video as defamation, because it could cause a retaliation with a 2nd video, causing more news sites to pick up the story again despite what is essentially a negative video promoting lies. Right now the goal is mostly damage control, getting the video off the front page when searching for the company name. There are a lot of positive videos but those aren't ranked as well because they aren't controversial. My only strategy is trying to promote those positive YouTube videos, but that may take a few months if it works at all. Does anyone have any advice on how to lower the rank or even get it delisted from Google for controversial content?