You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Betty Roberts.

ASSISTANT: How can I assist you today?

USER: I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, I am glad to help you with that.

USER: Sure.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, I didn't find any reservation on your name in our database.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for opting us.