don't think you can without removing the hood.
however, in the boot, you'll see a red pull handle on the left side of the roof tray (top of the boot).
make sure that handle is pushed in (to the left) as far as it will go.
you may need to twist it 90 degrees to get it further in, as it can rest on the plastic catch (designed to work that way).
if that handle is out, then it disengages the motor, meaning it will spin around, but the roof won't move an inch.