As long as they are in the same subject, they can apply for a major change. Liberal arts are not allowed to change to science or engineering, but science and engineering can apply for changing to liberal arts.
Freshmen will have an opportunity to change their major before the end of last semester, and the school's educational administration website will publish the matters and conditions that need attention when changing majors, such as how many credits to take (generally not less than last semester 15 credits, depending on the major). Transfer to professional examination subjects for English, computer and prescribed subjects (transmission lines to civil engineering should be mathematics, the specific number is not clear), and then the school ranks and delineates the scores according to the scores of candidates applying for transfer to major and publishes the list of candidates who have passed the line. Generally, it can be evaluated from the proposal of transferring to the college and give opinions on whether to agree to transfer.
In addition, as long as you have spare capacity, you can choose to minor in double degrees in the second semester. This is also a good way to make up for not being able to enter your favorite major.
In fact, your major in transmission line engineering is already very good. It's easy to find a job because both Tsinghua and the top three universities in China offer it. Of course, if you like civil engineering, you should study hard from the first semester and don't be playful. As long as you don't fail the course and violate the school rules, you can pass the exam as you wish.
Welcome to Three Gorges University!