<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Planner\Plans\Item\PlannerPlanItemRequestBuilderDeleteRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new PlannerPlanItemRequestBuilderDeleteRequestConfiguration();
$headers = [
'If-Match' => 'W/"JzEtVGFzayAgQEBAQEBAQEBAQEBAQEBAWCc="',
];
$requestConfiguration->headers = $headers;
$graphServiceClient->planner()->plans()->byPlannerPlanId('plannerPlan-id')->delete($requestConfiguration)->wait();