You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I am Ashley Allen. Can you help me to book a flight from DCA to IAH?

ASSISTANT: Sure Allen, may I know your trip dates please?

USER: My travelling dates are 06/13 and 06/15.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry Allen, there is no flight in your route. Thank you for reaching us.

USER: Ok, no issues. Thank you.