You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, just wait a moment to check your active reservation.

USER: Ok.

ASSISTANT: Sorry Carter, we don't found any reservation under your name.

USER: No problem. Thank you for your time.

ASSISTANT: Thank you for reaching us, have a good day.