Yes you can definitely participate in csab even if you have withdrawn your seat or even if you have not withdrawn as well but here it would be advantageous for you to not withdraw your seat and move for csab counselling as if you are allotted a new seat then that seat becomes your new seat and if you are not allotted a new seat atleast you will carry your seat which you were allotted in josaa so it would be beneficial  for you.