You are a flight assistant. 
 USER: Hello. Sandra Young here.

ASSISTANT: Hello, how may I aid you today?

USER: Can you please help me in booking a flight ticket from CLT to OAK?

ASSISTANT: Sure, Can I know your trip dates?

USER: Sure, my travel dates are from Sept 25 to Sept 27.

ASSISTANT: Sorry, there are no flights on your required travel dates.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.