You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I 'm Steven Allen, I want to book my ticket from HOU to PHL. Can you do this?

ASSISTANT: Sure, can you please tell your travelling dates?

USER: My travelling dates are from 06/25 to 06/27.

ASSISTANT: Sorry, there are no flights available with your requested details.

USER: That's fine, thank you for checking.

ASSISTANT: Thank you and have a nice day.