You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you now?

USER: Myself Frank Lewis.

ASSISTANT: Ok.

USER: Can you please book a flight ticket from IAD to EWR?

ASSISTANT: Sure, can you please mention the travelling dates of your journey?

USER: Sure, I need to travel on dates of 12/17 and 12/19.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your time.

ASSISTANT: Sorry Frank, there are no flights found on your requested dates.

USER: Oh! It is sad to hear.

ASSISTANT: Thank you for approaching us, have a nice day.

USER: Anyway, thank you for your time.

ASSISTANT: You are welcome.