To refinance, shop around for car loan rates and check your credit score to make sure you have a decent history. Once you’ve done that, start applying for refinancing. Apply with all your potential lenders within 14 days so that you’ll only have one hard inquiry documented on your credit report.
As far as actually closing, the process is the same as a traditional loan. The only extra things you need are information about your old car loan, including the balance, interest rate, and remaining length.