// request 2 - user's manager
var userId = "{{REPLACE_WITH_USER_ID}}";
var requestUserManager = client.Users[userId]
                               .Manager
                               .Request();
var resultsUserManager = requestUserManager.GetAsync().Result;
Console.WriteLine("   User: " + userId);
Console.WriteLine("Manager: " + resultsUserManager.Id);
Console.WriteLine("Manager: " + (resultsUserManager as Microsoft.Graph.User).DisplayName);
Console.WriteLine(resultsUserManager.Id + ": " + (resultsUserManager as Microsoft.Graph.User).DisplayName + " <" + (resultsUserManager as Microsoft.Graph.User).Mail + ">");

Console.WriteLine("\nGraph Request:");
Console.WriteLine(requestUserManager.GetHttpRequestMessage().RequestUri);