using System;

using System.Linq;

using System.Xml.Linq;

public class Program

{

    public static void Main()

    {

                var xml = @"<root>

​

<h:table xmlns:h=""http://www.namespaces.com/namespaceOne"">

  <h:tr>

    <h:td>Apples</h:td>

    <h:td>Bananas</h:td>

  </h:tr>

</h:table>

​

<h:table xmlns:h=""http://www.namespaces.com/namespaceTwo"">

  <h:name>African Coffee Table</h:name>

  <h:width>80</h:width>

  <h:length>120</h:length>

</h:table>

​

</root>";

​

        var doc = XDocument.Parse(xml);

        int count = 1;

        foreach (var namespaceAttribute in doc.Descendants().SelectMany(x => x.Attributes()).Where(x => x.IsNamespaceDeclaration))

        {

            doc.Root.Add(new XAttribute(XNamespace.Xmlns + $"h{count}", namespaceAttribute.Value));

            count++;

            namespaceAttribute.Remove();

        }

        Console.WriteLine(doc.ToString());

    }

}