Hello,
Due to various circumstances, all the students admitted under an institution maynot be able to pursue their course completely. So, if you are under such situation, you should take decisions on changing the institutions as soon as possible.
From your query, its clear that you have just completed your first year of btech in an institution. Just follow the steps mentioned below to get admission into another institution of your choice.
i) Let the college to which you will get admission know that you have completed one year of btech in another institution.  Institutions will always know a better way than laymen to get students admitted in their institute.

ii) Let your current college know about your decision to leave their institution.

iii) With proper procedures get an No Objection Certificate from your current college(college in which you are pursuing btech), get signed it from the respective officials and provide it to the other institute(college in which you are about to do your bsc).

NOTE:

i) Procedures for obtaining NOC's may vary from institution to institution.

ii) Fees paid while pursuing Btech in first year will not be refunded.