A refinance provides you with more time to repay your loan but is different from an extension. Typically, refinances require a principal pay down in addition to a finance charge. Refinances should only be used when absolutely necessary. You should, however, understand how they work in case of an emergency.
So how does a refinance work? On the original due date, you will typically pay off a portion of the principal and a finance charge. On your next due date, you will pay off the remainder of the principal and a finance charge.
Some lenders may not offer refinances, or you may not qualify for one, depending on your situation. A refinance is definitely not a long-term solution. You should repay your entire loan on time to reduce further charges.