You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: I am Samantha Baker, I plan to visit my sister on her birthday, can you help me with booking flight of fare 500?

ASSISTANT: Sure, can you please help me with your journey dates?

USER: I will fly on 07/23 and return on 07/25.

ASSISTANT: May I know your airport codes?

USER: My source airport code is TX-AUS and destination airport code is NC-CLT.

ASSISTANT: Thank you for your details. Sorry, we did not found any flights based on your given specifications.

USER: Ok, thank you for helping me.

ASSISTANT: Thank you for reaching us.