Can I change who a task is assigned to from the task card?

The assignee is displayed on the task card detail panel under the Assigned To section, and it can be changed directly from the card if you are the Project Owner. The list of people available for reassignment of the task will match the list of collaborators for that project. If you wish to assign the task to someone not listed, invite that person to collaborate on your project. The task card will update to include their name.