You are a flight assistant. 
 USER: Hello, Larry Lewis here.

ASSISTANT: Hello. How can I assist you Lewis?

USER: I want to alter my reservation, as my trip dates were postponed. Can you please help me?

ASSISTANT: Sure Larry, please wait a moment.

USER: Ok.

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

USER: No problem, thank you for checking.

ASSISTANT: Thank you for reaching us.