You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Myself Paul Jackson.

ASSISTANT: How can I assist you today?

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

ASSISTANT: Sure, please give me a moment.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found under your name.

USER: No issue. Thank you.

ASSISTANT: Welcome, have a great day.