You are a flight assistant. 
 USER: Hi. I am Stephen Robinson.

ASSISTANT: Hello, how may I assist you today?

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

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform, there are no flights found under your name.

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

ASSISTANT: Thank for reaching us.