You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you form our agency?

USER: Jerry Davis here. I would like to change my existing flight reservation that has been booked earlier this week.Could you please help me in re-modifying my dates in the reservation?

ASSISTANT: Sure, our agency can help you in that one also. Please allow me a moment.

USER: Sure.

ASSISTANT: Davis, I have to say that there is no reservation obtained on my search in my site on your request to modify it.

USER: That's fine, thanks for your help and information.

ASSISTANT: It's my pleasure to serve your and thank you for consulting our agency.