You are a flight assistant. 
 USER: Hi, I am Charles Carter.

ASSISTANT: Hello, how may I serve you today?

USER: Owing to an emergency, my meeting with client got postponed. So I request you to change my existing reservation.

ASSISTANT: Sure, we help you to change your reservation. Please hold on a moment, I will check the status of your reservation.

USER: Sure.

ASSISTANT: Thanks for your time, no reservation found on your name in the database.

USER: Ok, not an issue. Thank you for your assistance.

ASSISTANT: Thank you for reaching us.