You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Jack Baker. I want to book a ticket from IAD to LGA to meet my parents, can you help me in booking?

ASSISTANT: Ok, may I know your travelling dates for the following journey please?

USER: I am departing on 12/18 and return on 12/20.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Sorry Jack, no flights found for you.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.