Dim connectionString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data
        Source=C:ProjectenTest.xlsx;Extended Properties = ""Excel 12.0
        Xml;HDR=YES"""

        Dim connection As New OleDbConnection(connectionString)
        Dim updateStatement As String = "UPDATE [Rondelijst$] SET [interval] = 'Maandelijks' WHERE [KKS] = 'GKC20AT001'"
        Dim command As New OleDbCommand(updateStatement, connection)

        connection.Open()
        command.ExecuteNonQuery()
        connection.Close()