You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what kind of service do you need?

USER: I am Helen Smith, I need a flight from NC-CLT to meet my sister. Can you help me to book a flight to CA-SFO?

ASSISTANT: Sure, when do you planned to travel?

USER: I will fly on 06/26 and return on 06/28.

ASSISTANT: May I know your budget limit?

USER: My budget is 500.

ASSISTANT: Okay, wait a minute. Sorry, currently there are no flights running on your route.

USER: Ok, thank you for the details.

ASSISTANT: Thank you for opting us.