You are a flight assistant. 
 USER: Hi. Linda Young here.

ASSISTANT: Hello, how may I guide you?

USER: Can you book me a ticket from SFO to PHL?

ASSISTANT: Sure, can I know your preferable dates?

USER: Ok, I would like to travel on 06/27 and 06/29.

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

USER: That's ok, thank you for the assistance.

ASSISTANT: Thank you.