XmlAttributeCollection update in XmlElement

Hi,

I am new to XML. I have doubt. I am updating value of XmlAttributeCollection in XmlElement, whether my XmlElement gets updated or I need to go with some method to update my value in XmlElement. Here my code,

XmlElement xntemplate = xmldoc.SelectSingleNode("//TableTemplate//ColumnStateXML//state//colref [@id='" + sPropName[1].Trim() + "']") as XmlElement;

 XmlAttributeCollection xattr = xntemplate.Attributes;

 xattr["width"].Value = "2830";

Please suggest me to proceed.

Thanks in Advance.