In the Order View screen press the track wheel and select Remove Limit Order function from the side menu.
Once Remove Limit Order function is selected, the Warning screen will pop up
Press the BlackBerry track wheel and indicate your choice: YES or NO
(YES: remove limit order or NO: cancel this request)
WARNING SCREEN

When confirmed you will be redirected to the Order View screen
The Limit field should now be completely blank, since you have just removed the Limit Order from this existing order