You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be of your assistance?

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

ASSISTANT: Sure, may I Know your name please?

USER: My name is Katherine Garcia.

ASSISTANT: Thank you, no reservation found with your name.

USER: Ok, no problem.

ASSISTANT: Have a nice day ahead.

USER: Thank you.