How To remove xml tag and how to add new tag? asp.net c#

i upload one excel document and create dataset and convert the excel document to dataset the excel document have multiple sheets.if i have 3 sheets i have three tables in dataset.i merged into one table.(source1)

And i generate that table to xml below is example for this xml is dataset name source1 is datatable name and the tags F1,F2... tags is value of excel sheets.in every columns starting and ending i want one time start and ending like

....

...

how to do it.

EQUIPMENT TAG NO. OR SAP EQUIPMENT NO.