You can refinance both federal and private student loans - combining them into one private loan with a lower interest rate & lower monthly payment. You may be able to lower your payment even more by extending the term of your loan. However, your total repayment costs will increase due to paying more interest over time.
If you opt to refi your student loans, do so at least 6 months before you apply for a mortgage, and make all payments on time. This will help your credit score bounce back from the new line of credit used to refinance. Make sure to take the money that you save on your monthly student loan payments and save it for your down payment or closing costs!
If you have multiple federal student loans, you can consolidate your loans into one & decrease your monthly payments by extending the term of your loan. As with refinancing, this could cost you more over the life of the loan, so proceed with that in mind.