Symfony Console - unable to change input values with event

app.php

 <?php
 require "vendor/autoload.php";


 use Symfony\Component\Console\Application;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\Console\Event\ConsoleCommandEvent;
 use Symfony\Component\Console\ConsoleEvents;

 class TestCommand extends Command
 {
     public function configure()
     {
         $this->setName('test')
             ->setDescription('test')
             ->addArgument('name', InputArgument::REQUIRED, 'Who do you want to greet?');
     }

     public function execute(InputInterface $input, OutputInterface $output)
     {
         $output->writeln(sprintf("Hello %s!", $input->getArgument('name')));
     }
 }

 $dispatcher = new EventDispatcher();

 $app=new Application();
 $app->setDispatcher($dispatcher);
 $app->add(new TestCommand());
 $dispatcher->addListener(ConsoleEvents::COMMAND, function (ConsoleCommandEvent $event) {
     $input = $event->getInput();
     if($event->getCommand()->getName()=='test') {
         $newValue='jerzy';
         $event->getOutput()->writeln(sprintf("Changing argument from %s to %s!", $input->getArgument('name'),$newValue));
         $input->setArgument('name', $newValue);
     }

 });

 $app->run();

composer.json

{
    "name":"foo",
    "require": {
        "symfony/console":"~3.2",
        "symfony/event-dispatcher":"~3.2"
    }
}

result.txt

$ php app.php test fabien
Changing argument from fabien to jerzy!
Hello fabien!