If you have a z lock, you have an older awning, the newer ones do not have that feature.
The spring is located in the rear of the the roll (Patio awning) and can be very dangerous. you can remove the tension by disconnecting the rear arm and carefully unwind the arm. The arm can cause serious damage to you and your trailer if it get loose and unwinds by itself.
If you can remove the tension from the roll, you can remove the arm from the head and roll the awning up by hand, attach the hold downs to the heads and re attach the arms. Spring tension on the arm is shown here:
Awnings By ZipDee
Did I mention that the arms under tension can be very dangerous?