public function update($options = array()) {
        $options = new Values($options);

        $data = Values::of(array(
            'FriendlyName' => $options['friendlyName'],
            'AssignmentCallbackUrl' => $options['assignmentCallbackUrl'],
            'FallbackAssignmentCallbackUrl' => $options['fallbackAssignmentCallbackUrl'],
            'Configuration' => $options['configuration'],
            'TaskReservationTimeout' => $options['taskReservationTimeout'],
        ));

        $payload = $this->version->update(
            'POST',
            $this->uri,
            array(),
            $data
        );

        return new WorkflowInstance(
            $this->version,
            $payload,
            $this->solution['workspaceSid'],
            $this->solution['sid']
        );
    }