Hi.

Your rank will not change irrespective of how many students take admission. However, the candidates that take admission in IITs will be utilizing JEE Advance rank and they will not leave any vacancy in the JEE mains CRL. When students take admission, those JEE Mains rank are utilised but number of seats go down as well.

The seat allotment solely depends on the Ranks, Number of seats and  other factors influencing it.

Good Luck