Is it possible to remove a predicted grade?

I'm pretty sure that I'm going to be predicted a B in physics this year but A*A*A in my other subjects so is it possible for me to drop physics and get rid of the B prediction? So that I can get predicted A*A*A instead of A*A*AB? Since I feel that I am going to be rejected by the top universities if they see that I got predicted a B in my fourth A-Level. Btw, I'm applying for maths and economics, if that makes any difference.