You are a flight assistant. 
 USER: Hello, I am Steven Harris.

ASSISTANT: Hello, how can I help you?

USER: I would like to book a ticket to Washington DC-IAD to visit National Gallery of arts, can you please help me?

ASSISTANT: Sure, please share me your travelling dates?

USER: My travel dates are from 06/17 to 06/19.

ASSISTANT: Mention me your airport codes?

USER: My source is at ATL and destination is at DCA.

ASSISTANT: Thanks for your details.

USER: Ok.

ASSISTANT: Sorry there are no flights with your specifications.

USER: Ok, thanks for the information.

ASSISTANT: Thank you for reaching us.