You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Betty Johnson.

ASSISTANT: How may I assist you today?

USER: I have planned to visit Oakland, so I need to book a flight ticket from OAK to ORD.

ASSISTANT: OK, in which dates you are planned for the trip?

USER: My travelling dates are 03/08 to 03/10.

ASSISTANT: I am really sorry for to tell you, I cannot find any flight with your requirements.

USER: No issue. Thank you.

ASSISTANT: Thank you for contacting us.