You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

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

ASSISTANT: Sure, can I have your name please?

USER: Alexander Hall here.

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

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.