Although it seems like a good idea and should be simple to do, changing a car loan to a lease can’t be done.
First, only brand new cars are leased. Therefore, if you’re in the middle of a car loan, your car is now a used car, and can’t be leased.
Second, no auto finance company or bank would consider such an unusual transaction. There are no procedures in place to switch a loan to a lease.
If the objective is to lower your monthly payments, you can consider refinancing your car loan and adding more time to the loan, which reduces monthly payment amount. This approach is generally not a good idea in that it increases overall loan cost as well as putting you into an upside down situation that would be a problem if you later decided to sell or trade, or if your car is totaled in an accident.
Read the following article for more details: Can’t Afford Car Payments?