Combobox updating the database data

Question

I am developing a page that will serve to edit the support calls : open, pending and solved. But before the fields I created in Mysql I cannot update to update what I want.

<form role="form" method="post">
                    <div class="col-sm-6">
                      <!-- select -->
                      <div class="form-group">
                        <label>Select</label>
                        <select class="form-control">
                          <option value="Em Aberto" name="status_chamado" id="status_chamado" id="status">Em Aberto</option>
                          <option value="Em Andamento" name="status_chamado" id="status_chamado" id="status">Em Andamento</option>
                          <option value="Resolvido" name="status_chamado" id="status_chamado" id="status">Resolvido</option>                          
                        </select>
                        <button type="submit" name="botao" class="col-md-12 btn btn-success">ATUALIZAR</button>
                      </div>
                    </div>
                  </form>

It must update the "status_called" field of the "called" table that already has the value "Open" when the call is created, without changing the other values.

I tried using PHP concatenation but I got lost all over...

<?php                   
                  if(isset($_POST['botao'])) {
                  $status_chamado = $_POST['status_chamado'];                  
                  $cadastro = "UPDATE chamados SET status_chamado = ' " .  $status_chamado . " ' WHERE id_chamado = " . $id_chamado ;
                 

                    try{
                        $result = $conect->prepare($cadastro);                        
                        $result->bindParam(':status_chamado',$status_chamado,PDO::PARAM_STR);
                        $result->execute();
                        $contar = $result->rowCount();
                        if ($contar > 0){
                            echo 'foi';
                        }else{
                            echo 'n foi';
                        }


                    }catch (PDOException $e){
                      echo "<strong>ERRO DE PDO = </strong>".$e->getMessage(); 
                    }
                  }            
              ?>