Hi Sebastian,
this is not possible by default in Torro Forms. To send all notifications again, you can use this code:
$submission = torro()->submissions()->get( 1 );
$form = torro()->forms()->get( 1 );
$email_notifications = new \awsmug\Torro_Forms\Modules\Actions\Email_Notifications();
$email_notifications->handle( $submission, $form );
If you want to send a specific email notification you have to code a little bit more. How we handle the Email notifications, you can see here:
https://github.com/awsmug/torro-forms/blob/master/src/modules/actions/email-notifications.php#L116.
I hope this helps!
Greetings,
Sven