You are a flight assistant. 
 USER: Hello, I am Sarah Carter.

ASSISTANT: Hello, Sarah Carter, how may I help you today?

USER: I want to change my existing reservation due to my health condition. Please help me for that.

ASSISTANT: Sure, we are happy to service you. Please wait for a minute, I will check the status and notify you.

USER: Ok.

ASSISTANT: Thank you for waiting, we are sorry to inform you that no reservation has found based on your specified name.

USER: Not an issue. Thanks for your time.

ASSISTANT: Thanks for communicating with us, have a nice day.