You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Cynthia Collins.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: No problem, thank you anyway.

ASSISTANT: Thank you for opting us.