Hello,

Internal Sliding is mainly for students who have already joined in the Institutes through the counseling and got some branch , but trying to get another branch , this process is there in almost all national institutions ( NITS , IITS , IIITS ), it mainly occur in situation when some seats remains vacant even after completing all the rounds of counselling ( including spot admission / CSAB ) as some students not joining , then those sets are filled by internal sliding , students who want to get a better branch can opt for that vacant seat available

you can also slide your branch after 1st year ( Btech ) if you have a good pointer 9+ CGPA

Hope this clarifies your doubt

Best wishes for your future