Manually adjusting electric seats (W126)

Is it possible to manually move these electric seats backwards or forwards? My mom took my car last night and moved the seat all the way forwards, now it won't go back.
I'm 6'3" and just drove my little brother to school with the seat all the way forward. I'm not driving anywhere else. Too painful and too dangerous.
I've taken the seat out of the car, but I still can't see any way to manually move it back in the bracket.

Nicholas