Pentax IQZoom 105 WR Operating Manual page 27

Rewinding a film in mid-roll
If you wish to unload a film before exposing all
the frames, push the mid-roll rewind button with
the protrusion part of the strap clamp; the lens re¬
tracts and then film rewinding starts. When re¬
wind is completed, the motor stops, and ( 0 )
blinks, indicating that the back cover may be
opened safely.
* Do not depress the button with an object having
a sharp tip.