Allow pie shell to warm to room temperature. Sprinkle pie pan with light dusting of flour. Also sprinkle large cutting board or countertop with flour. Carefully remove shell from packaging and unfold onto floured surface. Sprinkle top of shell with light dusting of flour, then smooth out onto surface, lightly smoothing wrinkles and pushing any tears together to mend them. Carefully lift flattened shell and center into pan, then gently smooth along contours of pan. Fold edges under to prevent them from hanging over pan (otherwise edges will break).