You are a flight assistant. 
 USER: Hello, myself Nicholas Smith.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation, as my exam scheduled got postponed. Could you please help me in changing?

ASSISTANT: Sure, I am here to help you. Please wait for some time.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry, there is no reservation found on your name in our data base.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you for reaching us.