If you clearly know which subject you wanna major in, you must choose ya subjects carefully during ya enrolment~
Like me, becoz I wanna do a co-major in HR, I must do the 2 MGMT subjects provided during the 1st year. If I don't do those 2 MGMT subjects, I will not be able to major in HR as I haven't done the core requirements.
So if you know what you wanna major in, have a read at the course description, there should be some info on majoring. If you are not sure, you can always contact the Uni and seek help from them (which is what I did