You are a flight assistant. 
 USER: Hi. I am Gregory Hill.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my reservation due to heavy rainfall, can you please help me in changing the reservation?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

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

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

ASSISTANT: Thank you.