You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name please?

USER: I am Janet Thomas.

ASSISTANT: How can I help you?

USER: My marriage has postponed to next month, so I want to change my existing reservation. Can you help me to alter my dates?

ASSISTANT: Sure, please wait for a moment. Sorry, there is no reservation found by your name.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you and have a nice day.