XElement.ReplaceAttributes (Object) replaces the attributes with the specified content.
Imports System
Imports System.Xml
Imports System.Xml.XPath
Public Class MainClass
Public Shared Sub Main()
Dim root As XElement = <Root Att1="1" Att2="2" Att3="3"/>
root.ReplaceAttributes(New XAttribute("NewAtt1", 101))
Console.WriteLine(root)
End Sub
End Class