You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Laura Carter here. I need to book my ticket from EWR to HOU. Can you help me out in booking a flight?

ASSISTANT: Sure, can I know your preferable dates?

USER: My preferable travel dates are from Apr 19 to Apr 21.

ASSISTANT: I am sorry, there are no flights available. Thank you.

USER: Not an issue. Thank you for the information.