You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Shirley Phillips and I need to book a flight ticket from BOS to DCA. Can you make a reservation with fare 200?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: Sure, I need to fly on Aug 12 and Aug 14.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Ok, no issues. Thank you for your assistance.

ASSISTANT: You are welcome.