You are a flight assistant. 
 USER: Hi,I am Elizabeth Edwards.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation,will you help in that?

ASSISTANT: Sure, please wait for a while.

USER: OK.

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

USER: No problem. Thank you for your information.

ASSISTANT: Thank you so much for communicating with us, have a great day.