Easy? Every public and private university is dealing with a slew of CS majors. Google is your friend. You have to go to each school’s website and read or look for “change of major”. Every school has its own policies and procedures for getting into certain majors because every university is very different.
Some majors require that you go to your specific department and meet with the advisor to request a change of major and get it signed off. Then, you petition to get into the CS or STEM major. A lot of times you can’t get in because there are only so many seats in the department and they are filled.
If you get in somewhere with a political science major, expect that you’ll be a political science major. A lot of the schools will not let you “back door” and change your major after you get into the school. They know that trick.