Yes, you can. Go to the Manage Positions page found under AutoTrading menu on left hand margin, seen here:
For each open position, you have the ability to do the following Actions:
- decrease positions
- close positions early, and
- customize your own stop losses or profit targets
You will see a "signal being processed" message and then you will see the new signal in black text below the original signal which is green text.
When you modify an open position, that particular position will still close when the system itself goes flat that same position.
Only market orders are supported when changing the quantity of a position from the Manage Positions page. You can also add exit stops/limits manually to close (or partially close) a position, but you can only use market orders to decrease its quantity.
NOTE: If you want to increase positions, you can do so by increasing your Scaling.