You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Can you please book a flight from EWR to OAK?

ASSISTANT: Sure, let me know your travel dates please?

USER: Sure, I want to travel on July 19 and need to return on July 21.

ASSISTANT: May I know your connection limit?

USER: I need a direct flight.

ASSISTANT: Do you need any other preference?

USER: No.

ASSISTANT: Can I know your name please?

USER: Mary Martinez here.

ASSISTANT: Sorry to inform you that there are no flight services available on your given details.

USER: Ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for contacting us.