You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Patrick White.

ASSISTANT: How can I assist you today?

USER: I planned to meet my cousin in LAX, can you please help me to book a flight ticket from IAD?

ASSISTANT: Sure, I can help you with that. May I know your planned travel dates please?

USER: I prefer to travel on Jun 17 and Jun 19.

ASSISTANT: Do you have any specific class preference?

USER: I would like to travel in business class.

ASSISTANT: May I know in which airlines do you prefer to travel?

USER: I am comfortable with all the airlines.

ASSISTANT: Do you have any specifications regarding departure and arrival time?

USER: I planned to depart in afternoon and return back in morning.

ASSISTANT: Ok, please let me know if you have any other specifications.

USER: I would like to travel in a direct flight.

ASSISTANT: Ok, please wait a while.

USER: Sure.

ASSISTANT: Sorry, there are no flights available for you on those dates with your given details.

USER: Ok, not an issue. Thank you for your information.

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