If you can no longer pick up and deliver an order you have 'accepted' in the ROVA driver app, you need to cancel. Open "more details" at the bottom of the order and select "problem with order" button near the bottom of the screen.
Select the reason why you're abandoning the order and select the "submit" button.
You no longer need to deliver that order and are free to pick up different orders to deliver.
Watch this video for a screenplay of how this works in the app: