using System;

using System.Linq;

using System.Xml.Linq;

using System.Collections;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string input = @"<PublisherInfo>

    <PublisherName value=""1"">Askquestionzero Publisher</PublisherName>

    <PublisherLocation>Ph</PublisherLocation>

    <PublisherImprintName>Askquestionzero</PublisherImprintName>

    <PublisherLogo>

      <Tada>Remove this value and its content</Tada>

    </PublisherLogo>

    <PublisherURL>Askquestionzero.com</PublisherURL>

  </PublisherInfo>";

        XDocument doc = XDocument.Parse(input);

        doc.Descendants("Tada")

            .First()

            .Remove();

        doc.ToString().Dump();

        var elements=doc.Descendants("PublisherName")

            .Where(e=>e.Attribute("value") != null);

        foreach(var element in elements)

        {

            element.Parent.Add(new XElement("new-element", (string)element.Value));

        }

​

        doc.ToString().Dump();

        elements.Remove();  

        doc.ToString().Dump();

    }

}