Before leaving the vehicle, fully press the clutch pedal down, move the shift lever into R (Reverse), and firmly apply the parking brake. Once the shift lever has been placed in R (Reverse) with the clutch pedal pressed down, the ignition key can be turned to LOCK/OFF, then remove the key and release the clutch pedal.
See Manual Transmission Operation.
Chevrolet Cobalt Owners Manual. Rocking Your Vehicle to Get It Out
Turn the steering wheel left and right to clear the area
around the front wheels. Turn off any traction system.
Shift back and forth between R (Reverse) and a forward
gear, or with a manual transmission, between 1 (First) or
2 (Second) and R (Reverse), spinning the wheels as
little as possible. ...