Should I even ask, why do you want to get rid of them? If you want to get rid of all the styles then open your document in InDesign. Make a copy of it. Delete all the styles and replace with Basic Paragraph and None. Then save as .rtf
If you don't have the InDesign file and are just working off a .rtf file then you can do the same in Word. Select all the styles and delete them, replace them with the basic styles.