You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my reservation which was done last week. Can you help me?

ASSISTANT: Sure, may I know your name please?

USER: My name is Jack Hall.

ASSISTANT: Ok, please wait for moment.

USER: Sure.

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

USER: Ok, thank you for the information.

ASSISTANT: Thank you for opting us.