You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please share your good name?

USER: Lisa Green here.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your given name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.