I have a 2001 Nissan Altima GXE and the rear passanger door is permanently locked. I bought the car from another person and the door would only open from the INSIDE and not the outside. My friend accidentally put the childlock on and now it won't open from the inside. So the door is permanently shut and I need to know what I can do to fix it? Can it be done at home or do I have to take it to a mechanic?