Close Order Partially by given %?

Hi,

I want to close when order runs with +20 pips i would like to close running order % of order partially with some profit.

eg:

lot size: 1 lot

partial close parameter is = 50%

so when order is running above 20+ profit pips i would like to close the order partially 50% of lot size. according to settings it should close 50% of lot size 0.50 order partially, remains running with 0.50 lot.

i have tried coding. but it shows error message.

error message:

invalid lots number for OrderClose function
OrderClose error 4051

Code i tried:

    int orderstotal = OrdersTotal();
    int orders = 0;
    int ordticket[30][2];
    for (int i = 0; i < orderstotal; i++)
    {
        OrderSelect(i, SELECT_BY_POS, MODE_TRADES);
        if (OrderType() != OP_SELL || OrderSymbol() != Symbol() || OrderMagicNumber() != 1)
        {
            continue;
        }
        ordticket[orders][0] = OrderOpenTime();
        ordticket[orders][1] = OrderTicket();
        orders++;
    }
    if (orders > 1)
    {
        ArrayResize(ordticket,orders);
        ArraySort(ordticket);
    }
    for (i = 0; i < orders; i++)
    {
        if (OrderSelect(ordticket[i][1], SELECT_BY_TICKET) == true)
        {
            double LotPer = MathRound(OrderLots()*Lots/100);
            bool ret = OrderClose(OrderTicket(), LotPer, OrderClosePrice(), 4, Red);
            if (ret == false)
            Print("OrderClose() error - ", ErrorDescription(GetLastError()));
        }
    }

what wrong with this above code?