whmcsDNSManager/modules/addons/DNSManager2/mgLibs/custom/helpers/ClientMergeHelper.php

<?php

namespace MGModule\DNSManager2\mgLibs\custom\helpers;

/**
 * Description of ClientMergeHelper
 *
 * @author Mateusz Pawłowski <mateusz.pa@modulesgarden.com>
 */
class ClientMergeHelper
{

    public static function merge($fromUserID, $toUserID)
    {
        $zoneList = self::getZoneListAssignedToUser($fromUserID);
        if ($zoneList)
        {
            self::mergeZones($zoneList, $fromUserID, $toUserID);
        }
    }

    private static function getZoneListAssignedToUser($fromUserID)
    {
        return \MGModule\DNSManager2\models\custom\zone\Repository::factory()->byClientID($fromUserID)->get();
    }

    private static function mergeZones($zoneList, $fromUserID, $toUserID)
    {
        foreach ($zoneList as $zone)
        {
            try
            {
                $zone->clientid = $toUserID;
                $zone->save();
                \MGModule\DNSManager2\mgLibs\custom\manager\LogHelper::addSuccessLog('Migrate Zone', 'Migrate zone from client #' . $fromUserID . ' to #' . $toUserID, $zone->name);
            }
            catch (\Exception $ex)
            {
                \MGModule\DNSManager2\mgLibs\custom\manager\LogHelper::addFailLog('Migrate Zone', 'Migrate zone from client #' . $fromUserID . ' to #' . $toUserID, $zone->name);
            }
        }
    }

}