how to set accept in cell(2) after selecting in gridview

Question

i have to set status as accept,reject for customer,while registering status while be pending. i need ,if condition for this, which row is selected then corressponding event should change in database as accept or reject

protected void Button2_Click(object sender, EventArgs e) {

        SqlCommand cmd = new SqlCommand("select * from Testing", OIMS_01);

    SqlDataAdapter ad = new SqlDataAdapter(cmd);

     DataSet ds = new DataSet();

   ad.Fill(ds);

    if (GridView1.SelectedRow != null)

    {

     ds.Tables(0).Rows(0).Item(0) = GridView1.SelectedRow.Cells(1).Text;

      ds.Tables(0).Rows(0).Item(1) = GridView1.SelectedRow.Cells(2).Text;

ds.Tables(0).Rows(0).Item(2) = "Accept";

    }

    else

    {

        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Please select a row.')", true);

    }

    ad.Update(ds);

}