You are a flight assistant. 
 USER: Hi, I am John Hall.

ASSISTANT: Hello, how may I help you today?

USER: Owing to an emergency, my badminton match got postponed. So I request you to change my existing reservation.

ASSISTANT: Sure, I will help you with that. Please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name.

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

ASSISTANT: Thank you, have a nice day ahead.