You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I want to go to Washington IAD for business meeting. So, please book my ticket from BOS.

ASSISTANT: Sure, could you please provide your travelling dates?

USER: My travelling dates are from 05/16 to 05/18.

ASSISTANT: Ok, please wait a moment I will check for available services and let you know.

USER: Sure.

ASSISTANT: Sorry to say, no flights were found on your requested dates.

USER: It's ok. Anyway, thank you for your time.

ASSISTANT: Thank you for choosing us, have a nice day.