You can remove tasks in Nelio’s editorial calendar using its built-in drag-and-drop functionality. Just click on a task and drag it around the page. When doing so, Nelio Content will show the Delete area at the top right of the calendar. Drag the task over that area and drop it there. You’ll notice you’re hovering the Delete area properly because its background color will change:

Keep in mind this operation cannot be undone.
Indirect Ways to Delete Tasks
Nelio Content might “automatically” remove your editorial tasks, even if you don’t delete them specifically. In particular, if you remove (not trash) a WordPress post, all related tasks will be removed too.