You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Could you help me in booking a flight ticket from IAH to EWR?

ASSISTANT: Let me know your travelling dates.

USER: I want to fly on Mar 16, return on Mar 18.

ASSISTANT: Is there any airline preference?

USER: No.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Can I know your name?

USER: My name is Debra Lewis.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: No problem, thank you.

ASSISTANT: Thank you.