Make an appointment with your student advising center. This can be a jumping off point to see what else you could study without changing schools.
Read about other majors that interest you at the school, or even take a career aptitude test.
Take a course or two in a major you find interesting. If you don't have time to fit it into your schedule, consider auditing a course. You will take the course but not receive credit or a grade.
Talk to your advising center about internships and job shadowing. This can help you narrow your choices by examining what students who major in another area do as a career.
Talk to your advising center about what your school's policies are for switching majors. Each school will have a different procedure and each major will have its own set of required courses. Spend time finding out the requirements to make sure the switch of majors is feasible.