Clarification:
You cannot delete the built-in styles in Word; however, you can delete any
of the custom styles of a document (or template).
To delete a custom style, do the following: First display the Styles pane
(Ctrl+Alt+Shift+S). Then click the Manage Styles button. In the dialog box,
click the Import/Export button. Word displays the Organizer dialog box. You
should see the styles of the active document in the left pane. Select the
ones that you want to get rid of and click the Delete button.