To edit a task long-tap the task and choose Edit from the popup menu.

Or if you're viewing the task details you can long-tap the title, notes or elsewhere to automatically start editing. Or, choose Edit Task from the menu.
​

Once you've opened the edit view you can edit the details for the task.

You can also change the queue the task lives in from the edit view. Just tap on the current queue, which will open a full list of other queues to select from. All you need to do is save with the new queue to move the task!