Set post_parent for attachment

add_action( 'jet-engine/forms/booking/notification/insert_post', function( $notification, $manager ) {

	$form_id = absint( $manager->form );

	if ( 1853 !== $form_id ) { // Need to change the Form ID
		return;
	}

	$media_key = 'field_media2'; // Need to change the Media Field Name

	if ( empty( $manager->data['inserted_post_id'] ) ) {
		return;
	}

	if ( empty( $manager->data[ $media_key ] ) ) {
		return;
	}

	$attachment_ids = explode( ',', $manager->data[ $media_key ] );

	foreach ( $attachment_ids as $attachment_id ) {
		wp_update_post( array(
			'ID'          => $attachment_id,
			'post_parent' => $manager->data['inserted_post_id'],
		) );
	}

}, 20, 2 );