Qt Change TIMEZONE

void checkconcurrent::on_dateTimeEdit_start_dateTimeChanged(const QDateTime &dateTime)

{

    QString     date_format = "yyyy-MM-dd hh:mm";

    QDateTime   dates       = dateTime.toUTC();

                time_start  = dates.toString(date_format);

    qDebug() << "time_start = "  << time_start;

}