You can cancel an order in the Uber Eats app.
HOW TO CANCEL YOUR ORDER:
1. On the bottom menu bar, tap the receipt icon
2. Select your ongoing order
3. In the order screen, tap "CANCEL ORDER"
4. A pop-up appears to confirm your action, tap "CANCEL ORDER" again
5. After confirming, select a cancellation reason, then tap "DONE"
NOTE: If you cancel your order AFTER the restaurant started preparing it, you may only receive a partial refund.