def update(self, is_reserved=values.unset):
data = values.of({'<STR_LIT>': is_reserved, })<EOL>payload = self._version.update(<EOL>'<STR_LIT:POST>',<EOL>self._uri,<EOL>data=data,<EOL>)<EOL>return PhoneNumberInstance(<EOL>self._version,<EOL>payload,<EOL>service_sid=self._solution['<STR_LIT>'],<EOL>sid=self._solution['<STR_LIT>'],<EOL>)<EOL>
Update the PhoneNumberInstance

:param bool is_reserved: Whether the new phone number should be reserved

:returns: Updated PhoneNumberInstance
:rtype: twilio.rest.proxy.v1.service.phone_number.PhoneNumberInstance