save xml changes from data grid view

how can I save chenges of xml file loaded in data grid view , I wrote a code that load the xml file into the datagrid view , I might sometimes changes the values in the data grid view , how can I write and save the changes in the xml file ?

code to load the xml file :

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        OpenFileDialog1.ShowDialog()
        OpenFileDialog1.Filter = "xml (*.xml)|*.xml"
        Dim locate As String = OpenFileDialog1.FileName

        Dim xmlFile As XmlReader
        xmlFile = XmlReader.Create(locate, New XmlReaderSettings())
        Dim ds As New DataSet
        ds.ReadXml(xmlFile)
        DataGridView1.DataSource = ds.Tables(0)
    End Sub