You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, may I know your name?

USER: I am Jason Walker.

ASSISTANT: Please wait a moment.

USER: Sure.

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

USER: Ok, no problem.

ASSISTANT: Thanks for reaching us.