Convert single line text field into checkbox, radio, or drop down field type

[#1]

We can change a dropbox to a radio or checkbox field type. Now how about a way to convert a single line text fiend into a checkbox, radio, or dropdown?

Early in setup, someone created a critical field as a single line text field, and users have just been filling it out randomly so we can't pull reliable reports from it. They spell or abbreviate the fields differently, and we want to force them to picking a fixed list instead of typing it in.

We just don't want to lose the data completely and have to fill it out for all of our past jobs to fix this.