You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, may I know your name?

USER: Joshua Rodriguez here.

ASSISTANT: Please wait a moment.

USER: Sure.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thanks for reaching us.