Albin

With this pluginyou can face two goals:
· File Replace Sometimes you have an image used in several spots (slider, gallery, feature image, …) and if you remove it and upload it again, as it gets a new ID, you will need to select the new one all around but you could forget a place. To avoid it, use this plugin.
· File Rename Sometimes we upload a file as it comes from the mobile camera and later we realize that the file doesn´t have a ver SEO-Friendly name. Here you can rename the file.
None of both functionalities will breake any link where the image is pointed by its ID but this action doesn´t do a Search and Replace along the post entries.

FileRenameReplace

This plugin let the user renaming or replacing files without breaking links.

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.

FileRenameReplace vs Rename Users