You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my reservation due to my bad health. Can you help me with that?

ASSISTANT: Sure, I will you to change your reservation.

USER: Thank you.

ASSISTANT: Ok, please mention your name.

USER: My name is Barbara White.

ASSISTANT: Ok, please give me a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Ok, thank you for the information.

ASSISTANT: Welcome. Have a nice day.