You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I am Mark Thomas, planning to attend for music festival at Boston, BOS. Can you please book a direct flight for me on 08/27?

ASSISTANT: Sure. May I know your return date?

USER: I intend to return on 08/29.

ASSISTANT: Let me know your source code.

USER: Philadelphia, PHL is my source point.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no direct flight available with your given requirements.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you.