You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation.

ASSISTANT: Sure, I am here to help you out. May I know your name please to proceed further.

USER: Donald Miller here.

ASSISTANT: Donald Miller, we haven't found any reservation under your name in our database.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for approaching us.