You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Sarah Martin.

ASSISTANT: How may I guide you today?

USER: I am planning to attend music concert at OAK, can you please help me with booking a flight ticket from IAD?

ASSISTANT: Sure, I will help you with that. Can you please share your travelling dates?

USER: Sure, I would like to take off on 01/09 and return back on 01/11.

ASSISTANT: Wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for contacting us.

USER: You are welcome.