You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. how can I aid you?

USER: I am Robert Carter. Due to some issues I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Ok, please let me check with the status of your reservation to change.

USER: Sure.

ASSISTANT: There is no reservation found with your name in our database.

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

ASSISTANT: Have a nice day.