You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Wilson here.

ASSISTANT: How may I aid you?

USER: I would like to book a flight ticket from Las Visas.Could you please help me with booking a flight ticket from LAS to PHL?

ASSISTANT: Sure, I am here to help you out. May I know your travelling dates please?

USER: My travelling dates are 04/23 and 04/25.

ASSISTANT: Wait a moment please.

USER: Sure, I will wait for your response.

ASSISTANT:  Nancy Wilson, there are no flights available in your route.

USER: Not a problem, anyway, thank you for the information.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your service.