You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I would like to change my existing reservation which was made on the name of Patricia Parker. Can you help me with it?

ASSISTANT: Sure, may i know your name to check your reservation?

USER: I have already mentioned above.

ASSISTANT: Ok, please wait. Sorry, no reservation has been registered with us on your name.

USER: Ok, thank you.

ASSISTANT: Thanks for availing us to serve you.