You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, may I know your name please?

USER: I am Jason Jackson.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry Jason, there is no active reservation found with your name in our records.

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

ASSISTANT: Most welcome.