You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Ashley Allen. I am planning to change an existing  reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, please give me a minute.

USER: Sure.

ASSISTANT: Sorry Allen, there is no reservation available on your name.

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

ASSISTANT: You are welcome.