Somehow my passengers seatbelt managed to get the seat belt hooked on the lever used to raise/lower the seat, and I am unable to pull any slack out to free the belt.

The seat is currently at the furthest back position, raised as high as it can go, and the seat belt itself lowered to the bottom position - but there isn't enough slack to slip the belt back out.

Is there a way to remove tension from the belt, or will I need to detach the belt from the bottom. If detaching is neccesary what sort of tool do I need?