<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\RoleManagement\Directory\RoleAssignments\RoleAssignmentsRequestBuilderGetRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new RoleAssignmentsRequestBuilderGetRequestConfiguration();
$queryParameters = RoleAssignmentsRequestBuilderGetRequestConfiguration::createQueryParameters();
$queryParameters->filter = "roleDefinitionId eq '62e90394-69f5-4237-9190-012177145e10'";
$queryParameters->expand = ["principal"];
$requestConfiguration->queryParameters = $queryParameters;
$result = $graphServiceClient->roleManagement()->directory()->roleAssignments()->get($requestConfiguration)->wait();