You can mail your application stating your request to change the course to your preferred course at undergraduate2020@admission.du.ac.in (mailto:undergraduate2020@admission.du.ac.in) or you can contact 8860589343 (10AM-5PM Mon-Sat). This mail id and contact number are already there on their official website to address any admission related queries. For DU college prediction use this link https://university.careers360.com/delhi-university-college-predictor?icn=University%20of%20Delhi,%20Delhi_clgpd&ici=University%20of%20Delhi,%20Delhi_question_detail