You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Gregory Perez want to change my reservation due to prepone of my meeting. Can you help me in changing?

ASSISTANT: Sure, we are here to help you. Please wait for a while, I will check the reservation list on your name to change it.

USER: Ok.

ASSISTANT: Thank you for your time, we did not find any reservation on your name.

USER: Ok, thank you for your help.

ASSISTANT: Thank you for reaching us.