Reverting means undo the effects of one or more edits, which results in the page being restored to a previous version. However, reverting good-faith actions of other editors may be disruptive and can even lead to the reverter being temporarily from editing. Read the (part of the policy). Other Wikipedia to check out: and .
Another easy way: Restore a past version of the page. To do this:
The MediaWiki software sometimes enables editors to easily revert (undo) a single edit from the history of a page, without simultaneously undoing all constructive changes that have been made since. To do this, view the page history or the diff for the edit, then click on "undo" next to the edit in question. The software will attempt to create an edit page with a version of the article in which the undesirable edit has been removed, but all later edits are retained. There is a default edit summary, but this can be modified before saving.
It is also possible to undo several consecutive edits, even if they conflict among themselves: view the "diff" to be removed (by selecting the two extremal revisions in the history and clicking "compare selected revisions"), and click the "undo" link.
This feature removes the need to manually redo useful changes that were made after the edit that is being reverted. However, it will fail if undoing the edit would conflict with later edits. For example, if edit 1000 adds a paragraph and edit 1005 modifies that paragraph, it will be impossible to undo edit 1000 automatically. In this case, you must determine how to resolve the problem manually.
Rollback links appear on the user contributions pages, user watchlists, history pages and diff pages. Note that in the last case, rollback links can be misleading, since reversion is not necessarily to the old version shown (the diff page may show the combined result of edits, including some by other editors or only part of the edits the rollback button would revert). To see the changes the rollback button will revert, view the specific diff that compares the last version from the last editor with the last version from the previous editor.
Rollback works much more quickly than undo, since it:
On the other hand, it is not as versatile as undo, since it does not allow specification of which edits have to be undone. One may want to revert more or less edits than the rollback does or edits that do not include the last edit. It also does not allow adding an explanation to the automatic edit summary. Rollback may only be used in certain circumstances; most commonly to revert obvious vandalism.
Rolling back a good-faith edit, without explanation, may be misinterpreted as "I think your edit was no better than vandalism and reverting it doesn't need an explanation". Some editors are sensitive to such perceived slights; if you use the rollback feature other than for vandalism (for example, because undo is impractical due to the large page size), it is courteous to leave an explanation on the article's talk page or on the talk page of the user, whose edit(s) you have reverted.
If someone else edited or rolled back the page before you clicked the "rollback" link, or if there was no previous editor, you will get an error message.
When the rollback links on the contributions list are clicked, the revert and the original edit that you are reverting will both be hidden from recent changes, unless you click the "bots" link in the Recent Changes to set hidebots=0. The edits are not hidden from contributions lists, page histories or watchlists. The edits remain in the database and are not removed, but they no longer flood "Recent changes". The aim of this feature is to reduce the annoyance factor of a flood vandal, with relatively little effort. This should not be used for reverting a change you just don't like, but is meant only for massive floods of simple vandalism.
You will then see a list of past edits and a thumbnail graphic of each. Logged-in users will also see a "Revert" link for versions other than the current one. Click on a Revert link to make the change.
If the image is at Wikimedia Commons you must click through to the image page there to do the revert. You will need to be logged in at Commons.