Negative Wikipedia articles are a two-sided problem. Because Wikipedia can be edited by anyone, you could simply edit the Wikipedia article, or have someone else do it for you. This would instantly change it from negative to positive. But if someone doesn't like your edit, they'll just 'roll it back' to its original state. The second issue with a negative Wikipedia page is the strength of the site itself. It tends to show up high in search results because Google considers it one of the strongest sites on the internet. At last check, it had a Google Page Rank of 9, and a Moz Domain Score of 100 (out of 100). It is extremely difficult if not impossible to suppress Wikipedia because of its strength.
Difficult to Remove
It is nearly impossible to move a Wikipedia page down in search results because in order to do so stronger sites must be promoted to appear above it in search results. It can be done, but it is highly challenging. Even when successful, a negative Wikipedia article is normally only suppressed to the third or fourth position on the first page of search results. The most common way to displace Wikipedia is by creating highly relevant and aggressively promoted websites and other content. The creation of high quality content and websites is resource-intensive, thus the costs to displace a negative Wikipedia article are generally high.
As in George Orwell's book 'Animal Farm' incremental change has proven to work in many cases. Minor edits by multiple parties to a Wikipedia page over a long period of time often go unnoticed. This is a 'paid shill' tactic, and is often frowned upon, nevertheless it exists. Some online reputation firms use many experienced editors located in diverse geographic areas (IP addresses) to make changes to Wikipedia. When another editor challenges their work, these seemingly unconnected editors band together to refute the third-party editor. People often back down when challenged by a group of people, especially when the changes seem minor.
It is important to note that changes to Wikipedia must be rational, factual, and defensible. Often the best way to change a Wikipedia page is so simply soften the language bit by bit over time. For example, start by having one editor soften a few words. Then a few days later, have another editor from a different IP address soften a different part of the language. Gently but firmly defend changes anyone finds problematic. If the worst part of the page is located near the top, have an editor move problematic paragraphs down to where they are less obvious. It is a slow process, but often worth the work that goes into it.