You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to make some modification in my reservation. Can you help me out please?

ASSISTANT: Sure, I will help you to do modification before that I need your name to search your previous reservation.

USER: Myself Cynthia Campbell.

ASSISTANT: Sorry, there is no reservation found on your name to change your reservation in our data base, I think may no be reserved.

USER: That's ok, no problem. Thank you for your information.

ASSISTANT: Welcome. Thank you for choosing us.