You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to change my existing reservation due to postpone of my seminar. Can you please help me?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Linda Smith here.

ASSISTANT: There is no reservation found under your name in our data base.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for contacting us.