You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Due to health issues, I want to change my existing reservation.

ASSISTANT: Sure, I am here to help you out. May I know your name please?

USER: Sure, Carol Taylor here.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Carol Taylor, we haven't found any reservation under your name in our database.

USER: Ok, no issues. Thank you for your kind information.

ASSISTANT: Thank you for choosing us.