You can change the priority of a card from the Kanban Board, or the Detail view of the card.
1. To change the priority/rank from the Kanban Board, double-click the card and modify the value. Click Submit to save.
2. To change the priority of a card from the Detail view, navigate to the card and select from the Priority list, select the priority. To change the rank, enter a new rank.

The priority is indicated by the color code applied to the stars that appear on the card when the user story is placed on the card.