Yes, you can convert an open normal order into a stop-loss order by following these steps:
Visit the Order Book and click on the normal order you wish to modify
Tap on the Modify Order button.
This will reopen the order entry screen for you to make changes.
Select the SL Lmt or SL Mkt option under Order Type and enter the trigger price at which you want the order to be triggered.
Review and submit the modification request
Similarly, stop-loss orders can also be modified to a normal order by selecting the Market or Limit option under Order Type on the modification page.