Can I cancel or delete a task?
Not yet: there is no cancel or delete button. A task you don't need counts once, whether or not you accept it.
Tasks can't be cancelled or deleted for now. One you no longer need can be left as it is: it counts once, whether you accept it or not (only a task that fails isn't counted). A task waiting on you stays under Needs you until you accept it.
Still stuck?
Write to us and say what you were trying to do, what you expected and what happened instead. A screenshot helps.