You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I best serve you today?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, please share me your good name.

USER: John Allen here.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your good name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for availing us.