You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My name is Robert Brown. I would like to visit Washington to attend a cultural event so please help me with flight ticket booking.

ASSISTANT: Sure Brown, I am here to help you, can you help me with your travelling dates?

USER: I will start my journey on 10/19 and my return will be on 10/21.

ASSISTANT: Ok, may I know your airport codes?

USER: My airport codes are from EWR to DCA.

ASSISTANT: Ok, give me a moment.

USER: Ok.

ASSISTANT: Sorry Brown, there is no flight is available for you.

USER: It's ok, thank you.

ASSISTANT: Sorry for inconvenience. Thank you for choosing us.

USER: Thank you for your concern.