using System;

using System.Collections.Generic;

using System.Text;

using System.Linq;

using System.Xml.Serialization;

using System.Xml;

using System.Xml.Linq;

using System.IO;

using System.Data;

using System.Runtime.Serialization;

using System.Runtime.Serialization.Formatters.Binary;

using System.IO.Compression;

​

using NUnit.Framework; //NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/58172978/renaming-xdocument-element-names?noredirect=1#comment102736143_58172978

​

    public class TestClass

    {

        public static void Test()

        {

            var requestObj = GetXml();

            var xmlDoc = XDocument.Parse(requestObj);

            XNamespace newNamespace = "http://schemas.something.org/bla/07/WebServices.Stuff";

            // Move Addresses elements and children into the new namespace

            foreach (var e in xmlDoc.Descendants().Where(a => a.Name.LocalName == "Addresses").SelectMany(a => a.DescendantsAndSelf()))

            {

                e.Name = newNamespace + e.Name.LocalName;

            }

            // Optionally assign the namespace prefix "b" to some container element in scope.

            xmlDoc.Root.SetAttributeValue(XNamespace.Xmlns + "b", newNamespace.NamespaceName);

            Console.WriteLine(xmlDoc);

        }

        static string GetXml()

        {

            var xml = @"<root><SubElement>

<Addresses>

<AddressItem>

    <AddressLine1>RZN850PXKYG</AddressLine1>

    <AddressLine2>RYK57IT7Y9Z</AddressLine2>

    <AddressType>Physical</AddressType>

    <City>Some City</City>

    <PostalCode>9999</PostalCode>

    <Province>Some Province</Province>

    <Suburb>Some Suburb</Suburb>

</AddressItem>

</Addresses>            

</SubElement></root>";

            return xml;

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Roslyn Compiler; Environment version: " + Environment.Version);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Uncaught exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​