You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand today?

USER: I am planning to change my reservation due to health issue. Can you please help me out?

ASSISTANT: Sure, I am glad to help you to change it.

USER: Thank you.

ASSISTANT: Can I have your name please?

USER: My name is Shirley Williams.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for your time, there was no reservation found on your name to change it.

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

ASSISTANT: Thank you for choosing our service.