I think George is referring to client deletion.  He is correct that you can't delete a client, you can only "Make inactive" a client from the Clients dashboard.

You can, however, delete a return.  Just make sure you are deleting the one you won't ever need because you won't be able to recover that once it's done.  The simplest way to delete a return is to:

1. Go to the Tax Returns dashboard;
2. On the line of the return you'd like to delete, click on the dropdown (showing View return) under the ACTIONS column;
3. Select Delete return; and
4. In the popup, check that it is the correct return you'd like to delete, and hit Delete.

Poof, that return is now gone - forever - you've reached the point of no return.