<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Models\TokenIssuancePolicy;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new TokenIssuancePolicy();
$requestBody->setDefinition(['definition-value', ]);
$requestBody->setDisplayName('displayName-value');
$requestBody->setIsOrganizationDefault(true);
$result = $graphServiceClient->policies()->tokenIssuancePolicies()->byTokenIssuancePolicyId('tokenIssuancePolicy-id')->patch($requestBody)->wait();