You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I am Daniel Williams. I would like to book a ticket from PHL to IAH, can you please help me out?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: I am travelling on these dates 08/19 and 08/21.

ASSISTANT: Sorry, there are no flights found in our database.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for reaching us.