How can I get rid of my private student loan and switch to a federal loan with a lower interest rate?

In some cases private loans don't start accruing interest until you've finished school. If that's true for your loan then you don't need to pay it off yet. If your loan is already accruing interest I'd suggest doing a Google search for "private loan consolodation." There are plenty of companies that can help you reduce your rate.

I also have a Sallie Mae loan with an 8% interest rate. While the government does not allow you to take out loans to pay off private loans- you may be offered loans through financial aid. I've taken out the maximum amount of loan money I was offered from financial aid and used it to pay off my Sallie Mae account. It's not paid off completely yet- but it allows me a lower interest rate on at least part of my loan. If you can afford it, try to keep up with the interest payments on your private loan while it school because it's not fun paying interest on interest.

You can't switch them. You can only apply for consolidation and get a fixed interest rate, which will be based off of your credit. Any loan provider usualy does consolidation.