microkid

This plugin gives you full control over the permalinks for author pages. When using “pretty permalinks”, by default URLs to author pages are structured:
http://www.example.com/author/author-name/
With this plugin you can change the “author” part of these URLs into anything you like, for example:
http://www.example.com/editorial/author-name/ 
http://www.example.com/crew/author-name/ 
http://www.example.com/members/author-name/ 
http://www.example.com/posts-by/author-name/
The plugin will also automatically change links throughout your site that point to author pages. The URLs of author feeds are also changed.
Visit the <a href="http://www.microkid.net/wordpress/author-slug/" title="Wordpress Plugin: Author Slug" rel="nofollow ugc">plugin’s homepage</a> if you have any comments questions.

Custom Author URL

Customize the author slug in the permalink for author pages.

MMDeveloper

WP-SEO-Redirect-301 is a WordPress plugin that remembers your old urls and redirects users to the updated url, to prevent 404s when urls change
If you click on “SEO Redirect 301” menu link, you will see a list of old urls pointing to the new ones. Its here where you can delete ones you don’t want anymore.
Since version 1.9, you now get a sitemap that you can submit to google and bing. After installing the plugin, you can submit http://yoursite/301-sitemap.xml to google or bing.
Since version 1.8.0, you can now create custom urls in your admin post/page edit page. Login to your wordpress site, go to any post/page and scroll down. You should find a Meta Box called SEO Redirect 301s. If you submit a url here and then browse to this url, it will redirect you to the page/post your editing.
If you wish to manually submit a alias slug, make sure that you are using the Code Editor, not the Visual Editor. Edit the page or post, click on its 3 dots icon and click on Code Editor. Scroll down page until you see SEO Redirect 301s. Its here where you can manually enter in an alias slug.
Built by The Marketing Mix Perth: http://www.marketingmix.com.au

WP SEO Redirect 301

WP-SEO-Redirect-301 is a WordPress plugin that remembers your old urls and redirects users to the updated url, to prevent 404s when urls change

Custom Author URL vs WP SEO Redirect 301