quan_flo

This plugins allows administrators to rename wordpress usernames. 
The account owner is gets a notification email about the rename process.
Install, activate, and then go to the Users->Rename Usernames menu to rename user accounts.
More about me and my plugins
Since the year 1999 I do administration, customizing and programming for several forums, communities and social networks. In the year 2013 I switched from another PHP framework to WordPress. 
Because not all plugins I’d like to have exist already I wrote some own plugins and I think I’ll continue to do so.
If you have the scope at forums or social networks my other modules might also be interesting for you. <a href="https://wordpress.org/plugins/search.php?q=quan_flo" title="ifs-net / quan_flo WordPress Plugins" rel="ugc">Just take a look at my WordPress Profile to see all my Plugins.</a> Use them and if my work helps you to save time, earn money or just makes you happy feel free to donate – Thanks. The donation link can be found at the right sidebar next to this text.

Rename Users

This plugins allows administrators to rename wordpress usernames.

John Godley

Enhances the WordPress media library by allowing you to rename the underlying media files. Any change to a media item’s title will result in the media filename also being changed.
See the screenshot for more details of where to rename media files.
Note that all thumbnails will also be renamed. If you are using a caching plugin, such as WP Super Cache, then you will need to clear your cache so that any references are updated. This plugin does not update existing direct links to files (links inside a WordPress gallery will change).

Rename Media

Rename underlying media files from the WordPress media management interface

Rename Users vs Rename Media