using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        JObject feedbackData = new JObject();

        feedbackData.Add(new JProperty("realFake", "True"));

        if (feedbackData["realFake"]!=null)

            feedbackData["realFake"]= "False";

        Console.WriteLine(feedbackData.ToString());

    }

}

​