Rename Root Node in XML

// Create a new Xml doc object with root node as "NewRootNode" and 
// copy the inner content from old doc object using the LastChild.
        XmlDocument doc = new XmlDocument("FileName");
        XmlElement newRoot = docNew.CreateElement("NewRootNode");XmlDocument docNew = new XmlDocument();docNew.AppendChild(newRoot);
// The below line solves the InnerXml equals the OuterXml Problem 
        newRoot.InnerXml = oldDoc.LastChild.InnerXml;
        string xmlText = docNew.OuterXml;
// docNew contains the XML Document with replaced Root Node.