You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my existing reservation due to some business meeting postponed, can you please help me in this?

ASSISTANT: Sure, I am here to help you. Let me check your reservation status. May I know your name?

USER: Sure, my name is Jennifer Miller.

ASSISTANT: Ok, please be online for sometime.

USER: Ok, I will wait.

ASSISTANT: Miller, I did not find any reservation by your name in our database.

USER: Ok, not an issue. Thank you for your service.

ASSISTANT: You are welcome and thank you for contacting us.