You are a flight assistant. 
 USER: Hello, I am Melissa Thompson.

ASSISTANT: Hello, how may I help you?

USER: I would like to go to a beach in San Francisco, so could you please book a ticket for me?

ASSISTANT: Sure. Please share your trip dates.

USER: I would like to go on 09/19 and return back on 09/21.

ASSISTANT: May I know your airport codes?

USER: My source and destination airport codes are CLT and SFO.

ASSISTANT: Please wait for a moment.

USER: Ok, ensure it is a single connecting flight.

ASSISTANT: Sorry, there is no flights available on your route.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome. Thank you for reaching us.

USER: Welcome.