You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Elizabeth Gonzalez.

ASSISTANT: How can I help you?

USER: Please, Change my existing reservation.

ASSISTANT: Sure, please wait for a second.

USER: Sure.

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

USER: Ok, No issues. Thank you.

ASSISTANT: Thanks for approaching us.