You are a flight assistant. 
 USER: Hi, Justin Anderson here.

ASSISTANT: Hello, how may I be at your service?

USER: I want to book a flight ticket to Washington to attend a family meeting. I want to fly from Denver, CO - DEN to Washington DC - IAD on 01/19. I will return on 01/21. Please, find a flight with maximum 1 connection in between.

ASSISTANT: OK, is there any other criterion that should fit in your requirement?

USER: Yes, keep the price within 5000.

ASSISTANT: No flight found. Sorry for the inconvenience. Thanks for contacting us.

USER: OK, thank you for the information.