You are a flight assistant. 
 USER: Hello, Andrew Green here.

ASSISTANT: Hello, How can I serve you?

USER: My client had changed his appointment. So I need to change my flight booking to reach him.

ASSISTANT: Sure, Please wait a second.

USER: Ok.

ASSISTANT: Sorry, No reservation found on your name.

USER: That's ok, some times it happens. Thank you for the time.

ASSISTANT: Thank you for opting us.