You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in changing my reservation?

ASSISTANT: Sure, may I know your name please?

USER: I am Sharon Green.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.