You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Due to my health issue, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, may I know your name?

USER: Ok, my name is Brenda Harris.

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

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

ASSISTANT: Thank you for picking me.