public static void FNDMarkInventTrans(InventTransId _inventTransId,InventTransId _refInventTransId,InventQty _qtyTomark)
{
    InventTrans issueInventTrans;
    TmpInventTransMark tmpInventTransMask;
    Map mapMarkNow;
    container con;
    real qty;
    Map mapTmp;
    MapEnumerator mapEnumerator;

    InventTransOriginId issueInventTransOriginId =
        InventTransOrigin::findByInventTransId(_inventTransId).RecId;

    InventTransOriginId receiptInventTransOriginId =
        InventTransOrigin::findByInventTransId(_refInventTransId).RecId;

    InventQty qtyToMark = _qtyTomark;

    ttsBegin;

    issueInventTrans = InventTrans::findByInventTransOrigin(
        issueInventTransOriginId);

    [con, qty] = TmpInventTransMark::packTmpMark(
        InventTransOrigin::find(issueInventTransOriginId),
        issueInventTrans.inventDim(),
        issueInventTrans.Qty);

    mapTmp = Map::create(con);
    mapEnumerator = mapTmp.getEnumerator();
    while (mapEnumerator.moveNext())
    {
        tmpInventTransMask = mapEnumerator.currentValue();

        if (tmpInventTransMask.InventTransOrigin == receiptInventTransOriginId)
        {
            tmpInventTransMask.QtyMarkNow = qtyToMark;
            tmpInventTransMask.QtyRemain -= tmpInventTransMask.QtyMarkNow;
            mapMarkNow = new Map(Types::Int64, Types::Record);
            mapMarkNow.insert(tmpInventTransMask.RecId, tmpInventTransMask);

            TmpInventTransMark::updateTmpMark(
                issueInventTransOriginId,
                issueInventTrans.inventDim(),
                -qtyToMark,
                mapMarkNow.pack());
        }
    }

    ttsCommit;
}

reference code :
https://community.dynamics.com/ax/b/dynamicsaxnotesonthecuffs/archive/2013/01/08/marking-from-code-part-2