You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you at this moment?

USER: My name is Patrick Mitchell.

ASSISTANT: Welcome to flight booking agency Patrick.

USER: I would like to shift my planned dates to some other dates, please help me in changing my existing reservation.

ASSISTANT: Sure, I am oblige to help you with your request.

USER: Thank you.

ASSISTANT: Please wait a moment to check your previous reservation.

USER: Sure, take your time.

ASSISTANT: We regret to inform you that there is no reservation found on your name in our records.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching to our services, hope you have a great day.