'Update the ParticipantInstance
:param ParticipantInstance.ParticipantType participant_type: The Type of this Participant
:param unicode identifier: The Participant\'s contact identifier, normally a phone number.
:param unicode friendly_name: A human readable description of this resource
:returns: Updated ParticipantInstance
:rtype: twilio.rest.preview.proxy.service.session.participant.ParticipantInstance'

def update(self, participant_type=values.unset, identifier=values.unset, friendly_name=values.unset):

    data = values.of({'ParticipantType': participant_type, 'Identifier': identifier, 'FriendlyName': friendly_name})
    payload = self._version.update('POST', self._uri, data=data)
    return ParticipantInstance(self._version, payload, service_sid=self._solution['service_sid'], session_sid=self._solution['session_sid'], sid=self._solution['sid'])
