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

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation, as my  NBA play offs has been postponed. Please help me in changing?

ASSISTANT: Sure, I will help you. Please wait a moment. Sorry, there is no reservation found on your given name.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thanks for choosing us.