There will be professional exams, so in the first year, you should teach yourself or go to the department to listen to the professional courses you want to go to. After the first year of the exam, graduation will be delayed by one year, unless there are many overlapping courses in the two majors, they can transfer to the same level.

Some departments can't be transferred, such as archaeology in the outer court. . .

The above is the situation of Peking University. . I don't know the rest. .