using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""bad"": {

                ""Login"": ""someLogin"",

                ""Street"": ""someStreet"",

                ""House"": ""1"",

                ""Flat"": ""0"",

                ""LastIndication"": [

                  ""230"",

                  ""236""

                ],

                ""CurrentIndication"": [

                  ""263"",

                  ""273""

                ]

              }

            }";

        JObject jo = JObject.Parse(json);

        jo.Property("bad").Rename("good");    // works with property reference

        Console.WriteLine(jo.ToString());

        Console.WriteLine();

​

        jo["good"].Rename("better");           // also works with square bracket syntax

        Console.WriteLine(jo.ToString());

    }

}

​

public static class NewtonsoftExtensions

{

    public static void Rename(this JToken token, string newName)

    {

        if (token == null)

            throw new ArgumentNullException("token", "Cannot rename a null token");

​

        JProperty property;

​

        if (token.Type == JTokenType.Property)

        {

            if (token.Parent == null)

                throw new InvalidOperationException("Cannot rename a property with no parent");

​

            property = (JProperty)token;

        }

        else

        {

            if (token.Parent == null || token.Parent.Type != JTokenType.Property)

                throw new InvalidOperationException("This token's parent is not a JProperty; cannot rename");

​

            property = (JProperty)token.Parent;

        }

​

        // Note: to avoid triggering a clone of the existing property's value,

        // we need to save a reference to it and then null out property.Value

        // before adding the value to the new JProperty.  

        // Thanks to @dbc for the suggestion.

​

        var existingValue = property.Value;

        property.Value = null;

        var newProperty = new JProperty(newName, existingValue);

        property.Replace(newProperty);

    }

}

​