If you can get to the mechanism, the round piece where its retracted in to, take off the side cover, there will be a toothed wheel with a claw on a spring, pull back the claw and release as much as you need release the claw.
P.S. mind you fingers the spring is strong.
__________________ VELVET BLUE UK INDIVIDUAL , IM THE LAST
UNITED WE STAND DIVIDED WE FALL
I stepped in a plate of Pasta the other day - now I have to worry about my Carbonara footprint!