You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Please book a ticket from IAD to BOS.

ASSISTANT: Sure, can I know your travelling dates?

USER: Travelling dates are Dec 28 and Dec 30.

ASSISTANT: Sorry, there are no flights are available for given dates.

USER: Thank you.

ASSISTANT: Thank you for reaching us. Can I know your name.

USER: I am Jeffrey Edwards.