There is no built-in way for your visitors to “log out” of password protected posts once they’ve entered the password. Even logged in users cannot log out of password protected posts by logging out of their account. This plugin solves that problem by providing a link for your visitors to log out of password protected posts.
Setup
After installing the plugin, add the following code somewhere in your theme to display a link for logging out of password protected posts:
<?php do_action( 'posts_logout_link' ); ?>
This plugin is available for download to be used on your WordPress self-hosted installation.