You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, can you please tell me how can I assist you?

USER: My name is Helen Moore.

ASSISTANT: Ok.

USER: I am planning to celebrate a Flower festival in Charlotte, NC - CLT, so please book a flight ticket from San Francisco, CA - SFO.

ASSISTANT: Ok, may I know your travel dates?

USER: My departure day is 07/31, return day is 08/02.

ASSISTANT: Sorry, no flights found with your preferable requirements.

USER: No problem, thank you for your service.

ASSISTANT: Thank you for reaching us.