You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen Rodriguez.

ASSISTANT: How can I assist you today?

USER: I am scientist and I have to reach Boston to give a small seminar, so can you book a flight ticket from SFO to BOS?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: Thank you and my dates are 05/17 and 05/19.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: There is no flights found under your preferable details.

USER: Sad to hear that one, I can reach other agency when I have planned a new dates. Thank you for your information.

ASSISTANT: Welcome, have a great day.