You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I want to do some modification in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: On which name your ticket has booked?

USER: My name is Barbara Allen.

ASSISTANT: Sorry, no reservation found on your name in our database.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a nice day.