You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Stephen Miller.

ASSISTANT: How can I aid you today?

USER: Due to my health issues, I want to change my existing reservation. Please help me with that.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no active reservation found on your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you.