With negative rankings, as in your case you have 2 options.
Either ask the person posting to please remove the posting (which if it is very damming will be very difficult to get someone to remove)
Or out rank the negative ranking with positive ranking as 90% of the time people rarely scroll past page one of google.
Burying Bad Search Results with Good Ones
The concept behind burying bad search results is simple: create content that’s good enough to outrank them. But just like getting pages removed from the Internet, this is easier said than done. However it can be achieved with a little work, though none of it is difficult. Try these methods for outranking bad results with positive results for your name / business:
Use your name everywhere (do not use abbreviations – use the name that has the bad search result attached to it: It’s a good idea to use your real name on the websites or comments you’re using to improve your search engine results, but a better tactic is to simply be yourself everywhere online. If you’re not ashamed of what you’re posting, it’s always a good idea to use your real name. You never know what will spark Google’s interest. Always be on your best behaviour online — especially when using your real name.
Create content on multiple sites with the intention of outranking the negative content – using your real name always.
Optimize those pages with content & links to achieve rankings higher than the negative content, thus "pushing it down" to the 2nd page of results (or further. Optimize them by sharing them across the web and encouraging people to click on those links. If people don’t click on links google won’t find them and google won’t push those towards links towards the top.
Get your friends and family to click on those links to help google to find them – google can’t find a link unless it has been clicked – so the more that link gets clicked the more it will rank in googles data base search engine. Always make sure your name is the link or your name (full name) is in the article.
Get your name out there: You want your name (full name) to be on at least 10 sites or more – sites with high value (big websites with lots of traffic) – the more your full name appears on these sites the more chance you have of ranking your positive news or articles.
Authority Domains Using or creating content on high value, authoritative domains like Facebook, MySpace, Google+, LinkedIn, Twitter (if you have a good ranking high domain account change the name to the name that has the negative search term – for egsample – if your twitter handle is @bitconrules – add your name in there somewhere – like in the bio or heading – link your bad name with the good traffic) and other user-generated-content portals can be a very powerful strategy. You not only leverage the pre-existing strength of the domain for getting that content crawled and indexed, but can lean on the "authoritative domain" bias that Google shows in their rankings. Note - don't use Wikipedia for this, as they are more likely to find & report the negative or someone will just delete the content. Another great resource for profiles that do well on search results are local resources. Almost nothing does better than a .gov or .edu website on search results. Sign up for accounts and profiles on your local government website, local council website, local church website, the library, or create a profile on a school’s or university website. If you are commenting on any of these websites always put links back to your sites.
Maintain active accounts: Typically, the more profiles you can set up, the better. But it’s best to only sign up for as many social media profiles as you can reasonably maintain: active profiles are better than dormant ones, not just for search results, but for your general positive reputation. Acquire plenty of friends, followers, and connections, and genuinely build a community on your social profiles. Participate in the network and make your profile stronger. Use things like Buffer or Hootesuite or other social media management tools to help you manage your accounts. Make sure you stay active.
Pages Already Ranking Well for the Query In most cases where reputation management is necessary, there are already pages ranking in the top 10-20 results that are positive or neutral in content and therefore potential targets for optimization. Although you may not control these pages or be able to optimize on-page factors, pointing links with optimized anchor text to them can nudge up their rankings and help you achieve your goal. So in other words you if there is positive content about yourself you want to create links on various webpages pointing people in that direction. Remember google can only see those links if people click on them – so place the links where you think people will click on them … like crumbs for birds… the more crumbs the birds eat the fatter they become – the more people that click on the positive link the higher and bigger that search term will become.
Make a noise: Charity - Sponsoring charitable donations using your name or taking part in a fun event or doing something crazy that will get you attention in a positive light will get press attention and give you positive linking’s. Also, media links have high traffic so will help with rankings.
Create multimedia: Google loves images and videos, so give the search engine what it wants. Post images with your name in the file name and alt tags, and develop videos as well — ideally, posted on YouTube, which is a part of Google.
Other ideas for positive attention:
Have a friend interview or reciprocate by interviewing a friend – this on Youtube and write it up in blog – create your own website with blog articles and links written by you and lots of things that are positive pointing back to you. Always remembering sign everything off with your full name.
Offer to write free content for other people’s websites with links or your name signed. Insert images with meta data description having your name in the back ground.
Own your own domain: If you can own your own .com. net. .org. Get a domain that says: mrjohnsmith.com – blog positive things about you and whatever your interests are from this blog page. This will create traffic around your name – positive traffic. If you can build 2 or 3 websites and put your name in the title of page you will be closer to achieving your goal. Make sure you name comes up regular on the site and is in the title data and meta data and tags.
Try create a podcast channel. These are very popular for ranking.
Interview people and let people interview you for the podcasts. All you need is your phone – no special tech needed. Try get on a podcast – but always remember you want to be on podcasts that have nothing to do with your pasts same goes for guest blogging and article writing.
Leave comments online: News articles, industry blogs, and other influential websites often do well in search engine results. Use your real name to register for the comment section on these websites, and leave thoughtful, useful comments. You may find that these comments float to the top of search results for your name. Be careful: if the comment results become prominent, they’ll be one of the top results for your name. This is a good thing — but only if what you’ve commented with is positive. Make sure you’re using appropriate language, proper grammar, and are offering something genuinely interesting or important in your comment.
Constant maintenance: setting everything up is not enough you will have to constantly manage this. You will constantly have to add new content – make sure you are constantly posting positive feeds comments and blog posts. Regular at least once a month is best better is weekly – the more you post the faster your negative reputation will be squashed down the rankings on google.