You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: Please book me a flight ticket from ORD to IAD to meet my family.

ASSISTANT: Sure, can you please provide your preferable dates of travelling?

USER: I have planned to travel on Apr 18th and return on Apr 20th.

ASSISTANT: Do you have any connection limit?

USER: I prefer connecting flight.

ASSISTANT: At what time would you like to depart and return?

USER: I am ok with any time.

ASSISTANT: On whose name I have to book the flight ticket?

USER: Richard Adams.

ASSISTANT: Please wait a moment to check the flights.

USER: Ok.

ASSISTANT: Unfortunately there are no flights running on your route with your required preferences.

USER: Ok, no problem. Thank you.

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