You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: Sure, may I know your name?

USER: Sure, I am Robert Thomas.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name in our data base.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.