You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I want to change an existing reservation due to my health issues.

ASSISTANT: Sure, I am here to help you with that. May I know your name please?

USER: Can you please check the reservation by the name Kimberly Mitchell?

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, but I am very sorry to tell you that, there is no active reservation found on your name in our database to change it.

USER: Not a big issue, anyhow thank you very much for checking the reservation status.

ASSISTANT: Most welcome, thank you for reaching us. Have a nice day.

USER: You are welcome.