var client = (from n in db.CLIENTs
                              where n.ID == id
                              select n).FirstOrDefault();
                if(client != null)
                {
                    client.CLIENT_NAME = name;
                    client.CLIENT_ADDRESS = address;
                    client.PHONE = phone;
                    try
                    {
                        db.SubmitChanges();
                    }
                    catch (Exception e)
                    {
                        MessageBox.Show(e.Message);
                    }