Unless they have recently changed the rules, admitted students are not restricted by major. When given the choice, many students do not graduate in their original major as they discover other interesting opportunities in their first year. By way of example: CS may discover robotics or BME while Biologists /Chemists switch majors both in and out. Data Science is discovered by many math and CS students. A good deal of solid information on job placement in different fields is also discovered. Dialogue with faculty, research teammates and interdisciplinary project/classroom activity also develop these new interests. Most first year work is basic foundation which leaves open choices as long as the selected university makes it possible.
This is an advantage! The range of opportunities out there are not widely know to many students. One mentoring or not mentoring teacher can make a difference.
A great deal has changed since I was a student there. We started these changes in the late 60’s.