I have two XML documents, identical in structure. If a element value in A is different than B, then it needs to be copied to B (or a copy of B).

Hi,

You can use the SelectNodes method of XMLDocument to select the particular node then you can modify the value for that.

Please check the below URL

http://social.msdn.microsoft.com/Forums/vstudio/en-US/d512b5d3-a98d-4970-a26b-15d07fd41e4b/get-xml-node-value-using-xpath-c

Best Regards

Muthuraja