wp_ajax_wp_remove_post_lock

function wp_ajax_wp_remove_post_lock() {
	if ( empty( $_POST['post_ID'] ) || empty( $_POST['active_post_lock'] ) ) {
		wp_die( 0 );
	}

	$post_id = (int) $_POST['post_ID'];
	$post    = get_post( $post_id );

	if ( ! $post ) {
		wp_die( 0 );
	}

	check_ajax_referer( 'update-post_' . $post_id );

	if ( ! current_user_can( 'edit_post', $post_id ) ) {
		wp_die( -1 );
	}

	$active_lock = array_map( 'absint', explode( ':', $_POST['active_post_lock'] ) );

	if ( get_current_user_id() != $active_lock[1] ) {
		wp_die( 0 );
	}

	/**
	 * Filters the post lock window duration.
	 *
	 * @since 3.3.0
	 *
	 * @param int $interval The interval in seconds the post lock duration
	 *                      should last, plus 5 seconds. Default 150.
	 */
	$new_lock = ( time() - apply_filters( 'wp_check_post_lock_window', 150 ) + 5 ) . ':' . $active_lock[1];
	update_post_meta( $post_id, '_edit_lock', $new_lock, implode( ':', $active_lock ) );
	wp_die( 1 );
}