You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what kind of assistance are you looking for?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, on what name ticket has been reserved?

USER: Kevin Thompson.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, we couldn't find a reservation on your name in the portal to change.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.