POST https://graph.microsoft.com/beta/policies/crossTenantAccessPolicy/default/resetToSystemDefault
// Code snippets are only available for the latest version. Current version is 5.x
// To initialize your graphClient, see https://learn.microsoft.com/en-us/graph/sdks/create-client?from=snippets&tabs=csharp
await graphClient.Policies.CrossTenantAccessPolicy.Default.ResetToSystemDefault.PostAsync();
// Code snippets are only available for the latest version. Current version is 6.x
GraphServiceClient graphClient = new GraphServiceClient(requestAdapter);
graphClient.policies().crossTenantAccessPolicy().defaultEscaped().resetToSystemDefault().post();
<?php
use Microsoft\Graph\GraphServiceClient;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$graphServiceClient->policies()->crossTenantAccessPolicy()->escapedDefault()->resetToSystemDefault()->post()->wait();