public

change_registered_post_type_slug.php

<?php
add_filter( 'register_post_type_args', 'lc_change_registered_post_type_slug', 10, 2 );
/**
 * Change the slug for a registered post type.
 *
 * @param array  $args      Array of arguments for registering a post type.
 * @param string $post_type Post type key.
 */
function lc_change_registered_post_type_slug( $args, $post_type ) {

	// Make sure we're only modifying our desired post type.
	if ( 'post_type' != $post_type )
		return $args;

	$args['rewrite'] = array( 'slug' => 'new-slug' );

	return $args;
}