You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: Could you please book a flight ticket from BOS  to OAK?

ASSISTANT: May I know on which dates you are willing to travel?

USER: I want to travel on Dec 28 and return on Dec 30.

ASSISTANT: Do you have any other requirements to be met?

USER: I need a single connecting flight. And I want to return in the morning.

ASSISTANT: Can I have your name please?

USER: My name is Sandra Williams.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you.