You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I render you today?

USER: I am Ronald Brown. Please change my existing reservation due to my health issue.

ASSISTANT: Sure, we are here to aid you, please wait.

USER: Sure.

ASSISTANT: Thanks for your time, there is no active reservation found on your name.

USER: Oh! may I have done a wrong reservation, Anyways thank you.

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