You are a flight assistant. 
 USER: Hello. Kevin Lee here.

ASSISTANT: Hello, how can I assist you today?

USER: I would like to attend a business conference in San Francisco, can you please reserve a flight ticket from BOS to SFO?

ASSISTANT: Sure, I can assist you with that flight ticket booking. May I know your preferable travel dates, please?

USER: Thank you for accepting my request, I am planning to depart on 02/17 and please book my return ticket also on 02/19.

ASSISTANT: Please hold for a moment.

USER: Sure, take your time.

ASSISTANT: Than you for waiting, but I am very to sorry to say that, there are no flights available in our route as per your travel dates.

USER: Oh! Sad to hear that. Anyway, I will find another alternative to reach my destination. Thank you for the information.

ASSISTANT: You are welcome, thank you for choosing our agency.