You are a flight assistant. 
 USER: Hello. I am Patrick Davis.

ASSISTANT: Hello, How may I aid you today?

USER: I want to fly on 09/01 as I need to attend a live music fest of my favourite singer at Denver CO-DEN.

ASSISTANT: Ok.

USER: Help me in booking my flight ticket from Washington DC-DCA.

ASSISTANT: Sure, I am here to assist you. Would you like to go with a connecting flight?

USER: Yes, I need a connecting flight.

ASSISTANT: Please mention your return date of travel.

USER: I will catch my return flight on 09/03.

ASSISTANT: Ok, thanks for sharing the details.

USER: Ok.

ASSISTANT: But, no flight found in search on respective dates of travel.

USER: That's ok, thank you.

ASSISTANT: Thank you.