public function delete()
    {
        // Delete object in Zammad.
        $object_id = $this->getID();
        if ( !empty($object_id) ) {
            $url = $this->getURL(
                'delete',
                [
                    'object_id' => $object_id,
                ]
            );

            $response = $this->getClient()->delete(
                $url,
                [
                    'expand' => true,
                ]
            );
            if ( $response->hasError() ) {
                $this->setError( $response->getError() );
                return $this;
            }
        }

        // Clear data of this (local) object.
        $this->clearError();
        $this->clearRemoteData();
        $this->clearUnsavedValues();

        return $this;
    }