You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, may I know your name?

USER: I am Carolyn Mitchell.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: It's ok, thank you.

ASSISTANT: Thanks for reaching us.