You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Elizabeth Walker.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation. Can you help me in doing this?

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

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

USER: That's ok, not a problem. Thank you for your information.

ASSISTANT: Thank you for consulting us.