You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide 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. Can you please share your name?

USER: Myself Sharon Baker.

ASSISTANT: Please wait for a minute.

USER: Ok.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for contacting us.