You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

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

ASSISTANT: Sure, I am mirthful to help you with that. Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.