<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Users\Item\Events\Item\Instances\InstancesRequestBuilderGetRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new InstancesRequestBuilderGetRequestConfiguration();
$queryParameters = InstancesRequestBuilderGetRequestConfiguration::createQueryParameters();
$queryParameters->startDateTime = "2019-04-08T09:00:00.0000000";
$queryParameters->endDateTime = "2019-04-30T09:00:00.0000000";
$queryParameters->select = ["subject","bodyPreview","seriesMasterId","type","recurrence","start","end"];
$requestConfiguration->queryParameters = $queryParameters;
$result = $graphServiceClient->me()->events()->byEventId('event-id')->instances()->get($requestConfiguration)->wait();