You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Welcome to American airlines.

USER: I am Richard Jones.

ASSISTANT: How can I help you?

USER: Can you please book me a flight ticket to DCA from IAD?

ASSISTANT: Sure, on which dates you want to travel?

USER: My travelling dates are from 12/17 to 12/19.

ASSISTANT: Please wait for a minute. Thanks for your patience, but I cannot find any flight with your travel dates.

USER: No problem.

ASSISTANT: Thanks for contacting us, have a great day.

USER: Thank you for your response.