1099-B: I accidentally selected "RS" instead of "RSU" under the type of investment I sold and now I can't change it. How can I change it?

On the 1099-B, under the "What type of investment did you sell?" question, I selected "Restricted stock awards (RS)" instead of "Restricted stock units" and hit Continue. When I tried going back to that screen, I no longer have the option to change the type of investment I sold (a.k.a. the drop down menu is no longer a drop down menu).

How can I change they type of investment?