@ Varun - U can leave the course if u are not interested. Follow the principle given in 3 iditos.
" Join any field of ur interest. " But dont change it later on, otherwise ur parents and frends will think that, u r confused and dont knwo wat to do. So, just think twise before leaving the ca course. And choose ur interesting carrier and stick to it.
Now ur querry for documents:-
According to me, there is no requirement to inform institute for this. No documents need to be submitted.
You are free, even u dont need to inform about ur articleship etc to ur institute, its ur own decision.
But i recommend u to keep all the documents, registration letters etc for future, if in case, u decide to rejoin the course u will need all ur documents.
Best of luck. & Say, "All is well...."