need help

when will mock rounds start? thinking about withdrawing from vit chennai cse core cat 3, in favour of msrit ISE or BMSCE CSE core (24xx rank)

but my main question was this, say for eg i put 5 cllg and branch preference for round 1 and didnt get shite, can i still put more options in round 3 (outside KKR region), or are my 5 choices from round 1 fixed and carried over to each succeeding round?

do lmk, thanks