PHP change href when condition is met

Im using a PHP foreach loop to walk through an array of hyperlinks. if a condition is met, i want to change the href of the hyperlink. if not, the loop can continue. I am able to echo the current href using: echo $node->getAttribute( 'href' ); However i'm not able to change it using: $node->setAttribute('href', "https://ift.tt/2TjGdB8);

Im missing something here, but i have been stuck on it for a while.

Full code:

  $dom = new DOMDocument;
  $dom->loadHTML($homepage);
  foreach ($dom->getElementsByTagName('a') as $node) {
    if ($node->getAttribute( 'href' ) == "https://www.website1.com"  ) {
      echo $node->getAttribute( 'href' );
      $node->setAttribute('href', "https://www.website2.com");
    }
  }
$html = $dom->saveHTML();

source https://stackoverflow.com/questions/67938720/php-change-href-when-condition-is-met