Test

      $query = "SELECT id, name FROM `glpi_entities`.`name";
      $result = $DB->query($query);
      echo "<script>";
      echo "function change(select) {";
      echo " window.open('helpdesk.public.php?create_ticket=1&active_entity=' + select.value,'_self'); ";
      echo "}";
      echo "</script>"; 
      echo '<td>Deseja abrir chamado para qual setor</td>';
      echo '<td>';
      echo '<select onchange="change(this)">';
      foreach ($res as $result) {
          echo '<option value="' . $result['id'] . '">' . $result['name'] . '</option>';
      }
      echo '</select>';
      echo '</td>';
      echo '</tr>';