You are a flight assistant. 
 ASSISTANT: Hello.

USER: Hello.

ASSISTANT: How may I guide you?

USER: I am Edward Hernandez. I would like to book a flight ticket from DTW to OAK.

ASSISTANT: Sure, can I know your preferable dates?

USER: I am planning to start on 07/14 and return back on 07/16.

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

USER: Ok, no problem. Thank you for the help.

ASSISTANT: Thank you, have a good day.