Help:Revert a page
Reverting is changing a Wikipedia page back to an older version of the page. Because Wikipedia can be changed by anybody, the MediaWiki software is designed to save every version of a page when it has been changed by someone. When a new version of the page is saved, the old version is kept in the page's change history, so that anybody can see who changed the page, when they did it, and what changes they made to the page. You can change the page back to any of the old versions in the page history, such as when something has been added or removed when it should not have been.
Rollback
Rollback is a MediaWiki feature that automatically reverts a page to the last change made by a different user with a single click. It is especially useful for vandals who make many bad changes one after another, as it reverts all of their edits at once.
The rollback feature can be used by all Wikipedia administrators and other logged-in editors who have been given thministrator. These users can see "rollback" links on the page history, "diff" pages, user contribution pages, the recent changes page, and other places. Clicking on the link will immediately revert the page to the last change made by a different user. The change summary will say "Reverted edits by X to last version by Y", with links to the contributions and talk page of the user who is being reverted. The edit will appear as a minor change in the page history.
If someone else has already reverted the page, an error message will appear.
Bot rollback
In cases of flood vandalism (lots of vandalism by one user in a short time), administrators can hide the vandalism from recent changes. To do this, add &bot=1 to the end of the URL used to access a user's contributions. For example, http://en.wikipedia.org/w/index.php?title=Special:Contributions&target=BadVandal&bot=1.
When you click the rollback links, the revert, and the original edit that you are reverting will be hidden from the default Recentchanges display. It does this by marking the edits as "bot edits" (edits by a robot), which are hidden from recent changes.
The edits are not hidden from contributions lists, page histories or watchlists. The edits are still in the database and are not removed, but they no longer show up on Recentchanges. This is done so flood vandals do not annoy people using recent changes. This should not be used for reverting a change you just don't like, but is meant only for massive floods of simple vandalism.
Revert wars
A revert war, or change war, is where two or more people keep on reverting to their own version. Revert wars do not help the aims of Wikipedia. They look bad, upset people and make the page history less useful.
Reverts should not be used for change wars. Use the talk page to discuss the problem and find something you can agree on.
If you are in a change war, never revert the page more than three times in the same day. On the English Wikipedia, people are blocked (not allowed to make changes) for a day for breaking this rule.
Ask other people what they think. Perhaps they can change the words of the text to stop the change war. If it does not stop, ask an administrator to protect the page. You can ask this on Wikipedia:Simple talk, or on the Wikipedia:Administrators page, under the "current issues" section.