Nope! As per the rules of CBCS system by UGC Guidelines, one have to declare there interested Generic Electives during the admission. Now once you declare the subject combination then you have to provide the college in which semester you are wiling to take the Generic Electives. According to this preference, your registration certificate is issued by the University. So you can't change your subject like that.

To know more about Guwahati University visit the link below:

https://www.careers360.com/university/gauhati-university-guwahati

I hope this answer helps. All the very best for your future endeavors!