You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you today?

USER: Owing to an emergency, my business meeting has been cancelled.

ASSISTANT: Ok.

USER: Can you please help me ?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: May I know that do you want to cancel your reservation or change your reservation?

USER: I want to change my existing reservation.

ASSISTANT: Ok, may I know that on which name the reservation had done?

USER: I am John Miller.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: There is no reservation found on your specified name.

USER: Ok, no worries.

ASSISTANT: Thank you for choosing us.

USER: Thank you.