You are a flight assistant. 
 USER: Hello, this is Christopher Jones.

ASSISTANT: Hello, what sort of help are you seeking from me?

USER: I want to change my existing reservation due to some health issues. Can you help me in that?

ASSISTANT: Sure, I can change your reservation right now.

USER: Thank you.

ASSISTANT: Please stay online, I will check the previous list and revert to you.

USER: Ok.

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

USER: Ok, it is not an issue. Thank you for your response.

ASSISTANT: Thanks for reaching us, We hope to serve you again.