Converting from text field to rich text

I presume that you mean data entry fields.  I suggest making a copy of the text field first and then changing the copy field to test.

The main thing is that for your existing data you will lose all you line breaks.

So, are you suggesting the copied field as a test just in case something goes wrong?  

How do I go about converting without losing those line breaks?  

re: So, are you suggesting the copied field as a test just in case something goes wrong?  

Yes, exactly.

When you copy a field it copies the data in all the records too.

As for preserving the line feeds, I have not ever tried to do that.  I don't have time to test right now, but its possible you can make a Formula Rich text field with a formula

SearchAndReplace([my text field], "\n", "<br>").

Then if that looks visually OK, try changing THAT field from a formula Rich Text to just Rich Text. If you get a chance to test before I do let me know if that works.

Worked like a CHARM, Mark!  Great thinking.  Thanks!

great!