You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, may I know your name please?

USER: Emma Gonzalez here.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: No problem, Thanks for the information.

ASSISTANT: Most welcome.