You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you with today?

USER: I need your help to book a ticket from IAH to IAD.

ASSISTANT: Sure, I can help you with that. May I know your name to proceed further?

USER: My name is Emma Mitchell.

ASSISTANT: Emma, can you please help me with your travelling dates?

USER: Departure date is 03/17 and return date is 03/19.

ASSISTANT: OK, let me check that for you.

USER: OK.

ASSISTANT: Emma, I am sorry to inform you that there is no flight available at your requested date.

USER: That's really sad. Anyways, thank u for the information.

ASSISTANT: You are welcome. Thank you for contacting us.