Your immigration attorney will be assisting you in the entire process and clarifying what you can and cannot do. On the basis you have an approved I-140 petition under the EB-2 category but you have not yet filed your application for permanent residency, if the I-829 is denied and you no longer have conditional permanent residency, then when your I-140 petition's priority date becomes current then you can apply for permanent residency under the EB-2 category.