You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Can I know your name please?

USER: Catherine Martin here.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: There is no reservation found with your given name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for opting us.