There is a surgery that I think is called a forehead recontouring or brow shave . They make an incision at the hairline and surgically altering the bone. In severe cases, the bone is taken out, reshaped, and placed back in the skull. If needed small titanium wires or screws twill hold the bone in place while it heals.

It's a very common surgery for males who have made the transition to female. Not implying anything! It does take away the slant. I don't know how common it is for daily plastic surgery. I never looked into to. I just know that it can be done from a show I recently watched on Discovery.