wp-notices.php
public function restore_notice( $id ) {
		$id     = self::$instance->get_id( $id );
		$notice = self::$instance->get_notice( $id );
		if ( false === $notice ) {
			return false;
		}
		return 'user' === $notice['scope'] ? self::$instance->restore_user( $id ) : self::$instance->restore_global( $id );
	}
public function restore_notice( $id ) {
		$id     = self::$instance->get_id( $id );
		$notice = self::$instance->get_notice( $id );
		if ( false === $notice ) {
			return false;
		}
		return 'user' === $notice['scope'] ? self::$instance->restore_user( $id ) : self::$instance->restore_global( $id );
	}
Restore a notice previously dismissed.

@param string $id the id of the notice.
@return void