On Friday, I turned in my 2012 LEAF after my 39 month lease was extended for a year. I only fulfilled 5 additional months of the lease extension (with 2 free months claimed initially). LEAF extensions are open-ended, and can be terminated at any time by the lessee.
The process for returning the car is the same as returning a normal lease. There's nothing special you need to do. Here's my experience.
1) Call up NMAC to schedule an inspection if you haven't already. It doesn't matter if the inspection was performed under the initial lease time frame or under the extended lease. Only one inspection is necessary. You should be present for the inspection. The inspector will need the keys, he'll need to start the car, and he'll need to pop the hood and open all doors- but he won't drive it. He'll take pictures. He'll note any damage or excessive wear, and then give you a copy of the inspection report. You'll need to keep this report in your car when you return the car. If there's any damage that doesn't fall under normal wear, you'll want to fix it or get charged the full retail price for repairs at the dealership if they find damage.
2) Empty out your car and then make an appointment with the sales manager at the dealership to return the car. I inquired about this at my dealership and was told no appointment was necessary, just come in before they close. You do not have to return the car to the same dealer. When I arrived at the dealership, however, the sales manager asked if I had an appointment...
3) Sign the odometer statement and lease termination statement. The sales manager asked me for the inspection paperwork and for the odometer mileage, punched it into the computer, and had me sign the end of lease statement and odometer statement. I was not asked to sign the dealer Vehicle Condition Report, and no inspection was performed at the dealer while I was there.
4) Drop off the key fobs. You'll need both of them.
5) After you leave, call up NMAC and inform them of the return. The dealership told me I didn't have to do this, but NMAC said I did. This is to prevent them from coming after you for your next bill, which you won't be paying. They will want to know which dealer, the miles on the car, the name of the manager you worked with, and if you have any questions. NMAC did not ask if I signed the dealer Vehicle Condition Report. I'm wondering if this was recently eliminated from their lease return process.
6) Call your insurance and have them cancel your LEAF policy.
7) If you live in a state that requires informing the DMV or SOS of a vehicle possession change, you'll want to do that too. This is to prevent the state from coming after you in the event some crime takes place with your (former) LEAF. I don't believe there's a provision for this in my state, however.
The whole process at the dealer was done in about 5 minutes from entry to exit. It was completely painless. There was minimal sales pressure to get me into another car (he merely asked me how I liked the LEAF and what I was planning on getting next, and that's it).