You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Amy Roberts here. I want to visit Los Angeles, can you help me to book a flight ticket from BOS to LAX?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I would like to take off on 10/25 and return on 10/27.

ASSISTANT: Ok, please wait for a while.

USER: Ok, take it.

ASSISTANT: Sorry Amy, there are no flights available for your desired dates.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.