Update next payment date for subscribers

update_next_payment.php

<?php
/**
 * Update next payment date for subscriptions.
 * Run this script using WP CLI:
 * $ wp eval-file update_next_payment.php
 */
$subs = [
	// ids of subscriptions to update
];

foreach ( $subs as $sub_id ) {
	$new_billing	= '2020-07-01 08:00:00';
	$sub = wcs_get_subscription( $sub_id );
	if ( $sub ) {
		$sub->update_dates( [ 'next_payment' => $new_billing ] );
		echo "updated: " . $sub_id . PHP_EOL;
	} else {
		echo "ERROR sub_id not found: " . $sub_id . PHP_EOL;
	}
}

You're welcome!