¿Quién puede cambiar el estado de la tarea?
The author of the task, people to whom the task is assigned and people with whom the task is shared can change the status of the task. Once you've shared a task with somebody, he or she gets access to it and can edit its properties.
You both see and work on one shared task, not on replicas. Once your peer changes something, it is automatically updated in your workspace as well. You do not have to reload the browser to see that update.
If someone makes changes to the task that is assigned to you, a task you commented on or a task that you chose to follow, you get notified about the changes in the activity stream and by email.