You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to health issues, can you help me in changing the existing reservation?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: May I know your name?

USER: My name is Rachel Mitchell.

ASSISTANT: OK. Sorry there is no reservation with your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.