<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Models\CalendarPermission;
use Microsoft\Graph\Beta\Generated\Models\EmailAddress;
use Microsoft\Graph\Beta\Generated\Models\CalendarRoleType;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new CalendarPermission();
$emailAddress = new EmailAddress();
$emailAddress->setName('Samantha Booth');
$emailAddress->setAddress('samanthab@contoso.com');
$requestBody->setEmailAddress($emailAddress);
$requestBody->setIsInsideOrganization(true);
$requestBody->setIsRemovable(true);
$requestBody->setRole(new CalendarRoleType('read'));
$result = $graphServiceClient->users()->byUserId('user-id')->calendar()->calendarPermissions()->post($requestBody)->wait();