Modified orders will be treated as the cancellation and replacement of an existing order with a new order. On certain exchanges, this may have the effect of subjecting modified orders to commission minimums as if they were new orders. For example, if an order for 200 shares is submitted and 100 shares execute, then you modify the order and another 100 shares execute, a commission minimum would be applied to both 100 share orders. Orders that persist overnight will be considered a new order for the purposes of determining order minimums.