Why don't you just load the file as text, and do approproriate
Replace
calls on it:
string myXML =
myXML = my.XML.Replace("<item>", "<NewItemName>").Replace("</item>", "</NewItemName>");
myXML = my.XML.Replace("<itemdetail>", "<NewItemDetailName>").Replace("</itemdetail>", "</NewItemDetailName>");
myXML = my.XML.Replace("<detail>", "<NewDetailName>").Replace("</detail>", "</NewDetailName>");
myXML = my.XML.Replace("<Header>", "<NewHeaderName>").Replace("</Header>", "</NewHeaderName>");
Of course, one has to wonder why you're doing this. It's completely unneccessary from a programming point of view. The file is what it is.