You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My planned trip was postponed so I want to change my reservation. Can you help me?

ASSISTANT: Sure, may I know your name please?

USER: My name is Samuel Davis.

ASSISTANT: OK, please wait for a moment.

USER: OK.

ASSISTANT: Sorry Samuel, there is no reservation found on your name to change your reservation.

USER: OK, thank you for checking.

ASSISTANT: Thank you, for consulting us.