how to sell my lease

I suggest you read the lease.

What FOR is saying, is you can't sell it. You are renting the vehicle, so you don't officially own it. You can transfer your lease to another person, if you no longer want to make the payments. Use a website like swapalease.com

Actually you may be able to sell the lease to a qualified individual. Reading the terms of your lease or contacting your leasing company would be helpful.