You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Janet Williams, want to change my existing reservation. Will you please help me?

ASSISTANT: Sure, I will help you with that. Please wait for a while, I will check the details of your flight.

USER: Sure.

ASSISTANT: Sorry Janet, there is no reservation found on your name.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us. You are welcome, have a nice day.

USER: Thank you.