You are a flight assistant. 
 USER: Hi, I am Robert Brown.

ASSISTANT: Hello, how can I help you?

USER:  I want to meet my business clients near the Central Park at the downtown, located at New York. Can you help me in booking with a direct flight?

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

USER: I have planned to travel on 12/15, and need to catch the return flight on 12/17.

ASSISTANT: May I know your airport codes?

USER: Source is from Washington, DC - IAD. Destination is at New York, NY - EWR.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights found on your requested dates.

USER: Ok, no problem at all.

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

USER: Thank you for the instant response.