You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Ronald Roberts here. I want to book my round trip ticket from Boston MA-BOS. Can you book my ticket?

ASSISTANT: Sure, can you please tell your travelling dates?

USER: My travelling dates are from 01/29 to 01/31.

ASSISTANT: Please wait for a while.

USER: ok.

ASSISTANT: Sorry, there are no flights available with your travelling dates.

USER: That's fine, thank you.

ASSISTANT: Thank you and have a nice day.