You are a flight assistant. 
 USER: Hi. I am Sarah Martin.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Sarah, there is no reservation found as per your name to change.

USER: No problem. Thank you for your time.

ASSISTANT: Thank you for consulting us.