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

ASSISTANT: Hello, how may I help you?

USER: Owing an emergence, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, I am here to help you. Please stand by.

USER: Sure.

ASSISTANT: Thank you, sorry no reservation found with your name.

USER: Ok, no issues.

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