You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: Myself Helen Roberts from Atlanta. I want to change my travel dates in my previous reservation. Can you please help me with that?

ASSISTANT: Sure, I will help out in changing the ticket.

USER: Thank you for your positive response.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: Oh! It's ok no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.