You are a flight assistant. 
 USER: Hello. I am Dorothy Davis.

ASSISTANT: Hello, how may I serve you today?

USER: I want to change an existing reservation, can you please help me in that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry we couldn't find any reservation with your name.

USER: That's ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for opting us.