You are a flight assistant. 
 USER: Hi, I am Thomas Lopez.

ASSISTANT: Hello,. How may I assist you?

USER: I want to attend my cousin's marriage at Philadelphia, can you book a flight for me with the price of 200?

ASSISTANT: Definitely. May I know your departure and return dates?

USER: My departure is on 02/06 and arrival is on 02/08.

ASSISTANT: Please provide your travel location codes.

USER: My origin is at IAD and destination is at PHL.

ASSISTANT: I am sorry, there is no flight available.

USER: Ok, no issues.

ASSISTANT: Have a nice day!.

USER: Thanks for your kind service.

ASSISTANT: Thanks.