What is the meaning of virtual vacancy in 2 nd round

Virtual vacancy means vacating your seat in pursuit of a better seat in 2nd round. For example in the first round of counselling, you got an admission in a college and joined the college but in order to opt for a better college/seat, you decide to opt for 2nd round. So this seat is nor vacant until you get another seat in the 2nd round. Neverthless, once your seat gets vacant, another candidate gets your seat.