You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Unfortunately, I would like to change my existing reservation, can you please help me in this intent?

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Elizabeth Edwards.

ASSISTANT: There is no reservation found under your name.

USER: Ok, no issues, anyways thank you for your information.

ASSISTANT: Thank you for choosing us.

USER: Most welcome.