You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Owing to an emergency, I just want to change my existing reservation. Can you please help me?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Please mention your name.

USER: Sure, my name is Emma Adams.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Ok, thank you.

ASSISTANT: Welcome, have a nice day.