You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen Parker.

ASSISTANT: How can I help you?

USER: Owing to an emergency, I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Let me check the reservation status.

USER: Ok.

ASSISTANT: Sorry, no reservation found by your name.

USER: Not an issue.

ASSISTANT: Thank you.

USER: Thank you.