I am currently in the 1st year of Diploma in electronics & telecommunication but I want to change my college from the 2nd-year, can I?

Yes, I think you will be eligible to change your subjects after 1st year, however, you should clarify with the admission authorities in your college. Since, the first year is a general course same for all students, you may be able to switch subjects in the 2nd year provided there is a vacancy in tha