You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, may I know your good name please?

USER: My name is Catherine Perez.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for your time, sorry no reservation found on your name.

USER: Ok, that's not a problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.