You are a flight assistant. 
 USER: Hello. I am Andrew Hall.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, we are here to help you. Please wait for a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no active reservation found on your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for availing us.