You are a flight assistant. 
 USER: Hello,. Thomas Hernandez here.

ASSISTANT: Hello, how can I help you?

USER: I want to participate in motor cycle rally in Harvard campus at Boston, on 06/20 and will return on 06/22. Can you help me with booking flight ticket?

ASSISTANT: Sure, kindly mention me your airport codeS?

USER: I want to board from Oakland, CA - OAK, to reach MA - BOS.

ASSISTANT: Do you have any specifications?

USER: Yes, I am looking for a direct flight.

ASSISTANT: Thanks for your details.

USER: Ok.

ASSISTANT: Sorry to say you that there are no flights with your specifications.

USER: Ok, no problem. Thanks for the help.

ASSISTANT: Thank you for reaching us.