Aston Martin DB11 Owner's Handbook Manual page 202

11. Use the small end of the roof emergency tool to remove the
screw (F) from the roof motor.
11.14
Convertible Roof
12. Use the large end of the roof emergency tool to disengage
the drive spline (G) and turn the motor one turn counter-
clockwise.
You must contact your Aston Martin dealer to reset the drive
to the roof latch motor.
If the roof is manually raised or lowered, both the tension
bow and the tonneau cover cannot be locked.