You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book a flight ticket from SFO to CLT?

ASSISTANT: Sure, help me with the trip dates?

USER: Sure, my trip dates are Dec 23 and Dec 25.

ASSISTANT: May I know your name please?

USER: My name is Christine Davis.

ASSISTANT: Do you have any preferences?

USER: My depart time is morning.

ASSISTANT: Sorry, no flights were available at this moment.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.