To delete a single form, click on Forms (next to Q&A) on the tool bar near the top of the program window. In the navigation pane on the left, browse to the form, click the plus sign next to it to expand the folder, click on the item below to highlight the form for that taxpayer, then right-click on the form and choose Delete Copy.
To delete a full return, you must have more than one return created. If you have more than one return you can click on File > Delete Return. You will be given a dialog box similar to one for opening a return. Choose a return and click Open. You will be prompted to delete.
To delete an entire return, in Client Manager right-click on the return you wish to delete and then click on Delete Client(s). You will be prompted for whether you want to delete the return file entirely from the system (Yes) or just remove the client from the Client Manager (No).