When an order fails for any reason, it is automatically added as a return to the depot for that route. The driver sees that they need to return any orders to the depot before completing the route.
Such orders can be identified in the details for a route by a red cross or status Cancelled. They appear in the list on the Orders panel as Not Done, until they are returned to the depot and the route completed. Then their status changes to Returned.
You may filter for Returned orders from the top Show: menu. See also Filter by status.
Select these orders. At the top of the Orders panel, click the three-dot icon and then Edit selected to reopen them. You may also move them to another date at the same time. Once completed, these orders show a status of Reopened and can be planned into a route the same as for all other Open orders.