<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Models\AccessReviewInstanceDecisionItem;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new AccessReviewInstanceDecisionItem();
$requestBody->setApplyResult('AppliedSuccessfully');
$requestBody->setApplyDescription('Completed by John Doe');
$result = $graphServiceClient->identityGovernance()->accessReviews()->definitions()->byAccessReviewScheduleDefinitionId('accessReviewScheduleDefinition-id')->instances()->byAccessReviewInstanceId('accessReviewInstance-id')->decisions()->byAccessReviewInstanceDecisionItemId('accessReviewInstanceDecisionItem-id')->patch($requestBody)->wait();