Reference:Renameuser

Extension: Renameuser

Overview
Description:	provides Provides a special page that allows user accounts to be renamed.
State:	stable	Dependency:	MediaWiki
Developer:	Ævar Arnfjörð Bjarmasont	License:	- GPL v2+
Type:	MediaWiki	Category:	Administration
Edition:	BlueSpice free, BlueSpice pro, BlueSpice Farm, BlueSpice Cloud
For more info, visit Mediawiki.

Features

The Renameuser extension provides a special page which allows authorized users to rename user accounts. This will cause page histories, etc. to be updated. If you want to rename an account "into" another, already existing one, you need the User Merge and Delete extension.  Note:

• In case CentralAuth is installed, you'll get a warning if you try to rename a local user from an account attached to a global account or to a username reserved by a global account; a check box to rename anyway will be provided (this requires caution). You should probably use CentralAuth's built-in Special:GlobalRenameUser and Special:GlobalRenameRequest/Special:GlobalRenameQueue.
• You will not be able to rename users to invalid usernames (which doesn't equal usernames which match a blacklist but includes for instance reserved usernames).

For more information please visit MediaWiki.