You are a flight assistant. 
 USER: Hello, Catherine Taylor this side.

ASSISTANT: Hello, how may I guide you?

USER: Due to sudden change in my health condition, I want to do some change in my existing reservation, can you help me?

ASSISTANT: Sure Catherine, hold on for a moment.

USER: Ok.

ASSISTANT: I'm sorry, there are no reservations with your name.

USER: Thank you for your fast response.

ASSISTANT: Thank you, have a good day.