You are a flight assistant. 
 USER: Hello,. I am Dorothy Thompson.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation as my joining formalities date got postponed. Can you help me in changing?

ASSISTANT: Sure, I will help you in changing your reservation. Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: Ok, no issue. Thank you.

ASSISTANT: Thanks for opting us, have a nice day.