GE oven doors that lock and unlock are part of self-cleaning oven safety designs. A GE oven door locks during the cleaning cycle to prevent extreme heat and vapors from escaping from the oven and harming people or pets. The door remains locked after the cycle until the oven reaches a safe temperature. Typically, problems unlocking the door occur when you don't wait for the oven to cool or the oven has malfunctioned in some way.
Wait for your GE oven to cool. Slide the lock latch handle left as far as possible from the locked position on the right and then open the oven door.
Start a new self-clean cycle and then stop it before it can heat the oven if you can't slide the handle completely left to unlock the door after the oven initially cools. Return the latch handle to the right side locked position and program the cycle -- press the "Self Clean" key on the control panel, set the time with the "+" and "-" keys and then press the "Start/On" key. Stop the cycle approximately 30 seconds after you press "Start/On" by pushing the "Clear/Off" key and then try to unlock the door again.
Unplug the oven at the electrical socket or flip the circuit breaker switch that corresponds to the socket to reset your oven's system. Wait 30 to 60 seconds, plug the oven in or flip the switch back to its original position and try moving the handle again.