Do you want to make this change permanent for every where in your database or do you just want to suppress the formattiong for a specific report or layout?
From your original post, I'd guess that you want a permanent change.
Use Replace field contents to strip out the formatting with this expression:
TextFormatRemove ( yourfieldHere )
First make a back up copy of your database as this will change every record in your table and can't be undone.
Then select show all records.
Then click/tab into this text field and choose Replace Field Contents from the Records menu and specify the "calculation" option.
For future records, you might want to add this auto-enter calculation to the field so that pasting formatted text into the field has the formatting automatically stripped out:
TextFormatRemove ( Self )
and clear the "do not replace existing value..." check box.
Wow, that worked perfectly. I never would have figured that out in a million years.