Unfortunately you cannot refinance a student loan while still in school because when you refinance a student loan you're basically taking out an entire new student loan with different terms and conditions and interest rates as well as payment terms.
The lender will want to know exactly how you're gonna be able to pay back the student loan when you go into refinance it and it's gonna be hard to convince the lender that you'll be able to pay back the loan when you go to refinance.
So you have to wait until you graduate college or leave college to refinance the student loan and hopefully by then you'll have a good job that will allow you to keep up with the student loan payments.