Am I eligible to sit for 2nd round of COMEDK counselling if I select any seat in the first round?

Yes,you can modify your selection by attending 2nd round of counselling. You will get an option before the second round that you can surrender the seat selected in the first round and then go for second round or you can go to the second round taking safe side without surrendering the seat. The new seat you will choose will automatically make your previous selection null & void.