if (source.Bars[i].Date == LongPos.EntryBar.Date)
    LongPos.CloseAtStop(i + 1, LongPos.EntryPrice - Stop, "LX Stop");
else
{
    if (LongPos.GetStop(i) < НовыйСтоп)
        LongPos.CloseAtStop(i + 1, НовыйСтоп, "LX Stop");
    else
        LongPos.CloseAtStop(i + 1, LongPos.GetStop(i), "LX Stop");
}