The laws of what's stylish and what isn't can vary between individuals or parts of the country. Just as having a curved baseball hat bill is considered chic for some, others find it a big fashion faux pas. Or you might just tire of wearing a hat with a curved bill and want to convert it for a new look. Regardless of trends, you can convert a curved bill to flat in just a few minutes.
Set an iron to steam and fill a spray bottle with water.
Spray the entire bill of the hat generously with water.
Press the iron against the bill and move it slowly around the surface area, including the corners.
Place the hat in a cool place away from direct sunlight to dry. Once the hat is dry it is ready for wearing.
Put a paper towel over the damp brim with a heavy book on top so the bill dries perfectly flat. You can also put the hat in the freezer to expedite the process and help the bill keep its new shape.