You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I would like to visit Downtown Aquarium with my friend at Houston, please help me in booking a ticket from DCA to IAH.

ASSISTANT: Sure, I am here to help you in booking. Could you please share your travel dates?

USER: My travel dates are 11/18 and 11/20.

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: May I know your name?

USER: My name is Michael Mitchell.

ASSISTANT: Sorry, no flights are available on your route.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome, thank you for reaching us.