Reverse SEO is the practice of taking actions for decreasing the rank of a page or website in Google and other search engine pages.
Reverse SEO may be used for penalyzing competition websites. It is then called negative SEO and the practice presents legal risks.
Reverse SEO may be a more legitimate practise when the purpose is to downrank a page or website which hurt brand or individual reputation. In this case, the technique used is often to try to place new webpages above the targeted page in SERPs and where possible to push down the "bad" page onto the second result page. It may also be tempting to use negative SEO for this situation.
Reverse SEO is an online reputation management tool use by dedicated agencies to protect their clients.
Reverse SEO can be used to suppress negative publicity that targets your company in Google, Yahoo, and Bing. By pushing bad press onto the second, third, and fourth pages of Google, those pages will be prevented from gaining traction or attention.