You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation as my plan to visit Boston has been postpone. Can you help me with that?

ASSISTANT: Sure, please wait for a moment. May I know your name please?

USER: I am Jessica Green.

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

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

ASSISTANT: Thank you for opting us.