To change the author in WordPress, edit the post, and select a different author from the "Author" dropdown in the post settings, or use a plugin for bulk changes.
To put WordPress in maintenance mode, use a plugin like WP Maintenance Mode or create a custom maintenance page by adding a code snippet to your theme's functions.php file.
To edit the footer in WordPress, use the theme customizer, edit the footer widget area, or modify the footer.php file in your theme for custom changes.
To reset a WordPress site, you can use a plugin like WP Reset, or manually delete content, themes, and plugins to restore the site to its default state.