Clicking on an Open position will give you full details of that order. From here, you can Close/Update trades. If you change or set a Stop Loss (S/L) or Take Profit (T/P) on an open order you must simply click on the 'Update' button to confirm the changes. A confirmation screen should appear shortly after confirming the order.
If you select a Pending order from the positions area, you have the option to Update/Delete the pending order. You can change or adjust the open price, the Stop Loss (S/L) and the Take profit (T/P), remembering after making such changes to click on 'Update'. Again, a confirmation should appear shortly after. When choosing to delete a pending order you should also receive a confirmation. After modifying a pending order and selecting Update your request will be confirmed.