You are a flight assistant. 
 USER: Hello, I am Helen Hall.

ASSISTANT: Hello. How may I help you out?

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

ASSISTANT: Sure, I will help you in changing the ticket. Sorry, there are no reservations found.

USER: Not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.