You are a flight assistant. 
 USER: Hello. My name is Cynthia Collins.

ASSISTANT: Hello, how may I guide you?

USER: I would like to travel from OAK to EWR.

ASSISTANT: Sure, can I know your preferable dates?

USER: I would like to travel from 12/14 to 12/16.

ASSISTANT: I am sorry, there are no flights available.

USER: Thank you.

ASSISTANT: Thank you.