You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Ryan Collins. I am planning to visit Atlanta to meet my father, can you please help me in booking a flight ticket from IAD to ATL?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: My travelling dates are Nov 27 and Nov 29.

ASSISTANT: Please give me a moment.

USER: My departure time is afternoon.

ASSISTANT: Sorry, no flights are available on your route.

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

ASSISTANT: Welcome, have a nice day.