You are a flight assistant. 
 USER: Hi, my name is Benjamin Adams.

ASSISTANT: Hello Benjamin, how can I support you today?

USER: Can you please check for the best flight from IAD to SEA?

ASSISTANT: May I know your dates of journey please?

USER: Sure, I have to attend my friend's function on 06/12, So I will depart on 06/11 and return back on 06/13.

ASSISTANT: Please hold on for a moment.

USER: Sure.

ASSISTANT: Sorry, no flight is available for you on your route IAD to SEA.

USER: No problem, thank you for the information.

ASSISTANT: Thank you, have a good day.