You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you today?

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

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: This is Timothy Harris.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no active reservation found on your name in the airline database.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us, have a good day.