Hii!

If you want to change your GE (General elective) subject from English to economics then definitely you can do so.

I don't think it will not effect your cgpa, but before changing please consult the proffesors of your college,  you can also consult to admin department regarding this.

The only benefit you get by studying same subject in all 6 semester is that you can do your Post Graduation with specialisation in that subject.

Hope it helped:)