You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Virginia Clark. Can you please help me with booking a flight ticket from DCA to BOS?

ASSISTANT: Please mention your travelling dates.

USER: Travelling dates are 08/02 and 08/04.

ASSISTANT: Ok, do you have any other requirements?

USER: I would like to depart and return at evening.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: My pleasure.