Symfony2 Forms: remove an inherited field

FormType.php

<?php

class AccountCreationType eextends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options) 
    { 
        $builder
            ->add('partner_opt_in') 
            ->remove('global_opt_in'); 
    } 
    
    public function getParent() 
    { 
        return 'site_account_creation'; // defini un champ 'global_opt_in' 
    }
    
    public function getName()
    {
        return 'partner_account_creation';
    }
}