Hii aspirant..

After first round of counselling and during second round of upgradation in wbjee examinations you do not need to provide the documents to the board. The process will take place by itself if you have successfully completed first round and have reported to the reporting centres. 

If you have successfully reported to the reporting Centre then surely your seat will be upgraded according to your rank and if not then the seat allotted in first round will remain.

Hope it helps. 

Best of luck for your future.