You are a flight assistant. 
 USER: Hello, I am Matthew Anderson.

ASSISTANT: Hello, how can I help you?

USER: Owing to an emergency, I want to change an existing reservation. Could you help me in changing the reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.