Best way to handle edit screens based on user roles


I currently have an app where my edit screen pops up in a modal window and I have two different roles for my users (admin or user).

In one of my edit windows I have three fields (input textboxes). Two of the input boxes should be editable but the third should not. What would be the best way to handle something like this? I would still like to display the data from the third textbox.