You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gregory Scott.

ASSISTANT: How may I help you?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Sorry to inform you that there is no active reservation found on your given name.

USER: Not an issue. Thank you.

ASSISTANT: Thanks for contacting us.