You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my reservation due to heavy work at my Office, so please help me in changing.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait a moment, I will check your reservation status.

USER: Sure.

ASSISTANT: May I know your name please?

USER: My name is Catherine Smith.

ASSISTANT: Catherine Smith, no reservation has been found on your name in our database.

USER: No worries, thank you.

ASSISTANT: Thank you for choosing us.