Paragraph styles cannot be deleted, but you can rename and override your current styles.
How do I rename a style?
1. Double click the Paragraph Style name
2. Type your new name
3. Press Enter on your keyboard to save
How do I override a style?
1. Select the Paragraph Style you want to edit
2. Use the Design Panel to edit your new style
3. Click the check mark to save and override the current style.