How do I use “RPL” to replace an order?

An order may be modified if the routes and your broker allow it. Double-click the open order in your Orders window to load it onto the Montage window, make your changes, and then use the “RPL” button to replace the order. Right-click on the order and select “Edit Trigger Order” to add or edit a Trigger Order in this primary order. (Source: DAS Trader User Manual