You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I be of your assistance?

USER: Actually I want to change my existing reservation due to some health problem. Can you help me?

ASSISTANT: Sure, I'll help you with this. Please let me know your name to check the reservation status.

USER: Thank you. Ok, I am Brenda Smith.

ASSISTANT: Ok, please wait a moment I will check and revert to you.

USER: Ok.

ASSISTANT: Thank you for waiting, we did not found any reservation on your name.

USER: Ok, not a problem. Anyway's thank you for your information.

ASSISTANT: Thank you for availing us.