You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I am Helen Allen, I need to change my existing reservation can you help me out?

ASSISTANT: Sure, I am here to help you. Sorry, there is no reservation found on your name in our database.

USER: That's not an issue I will choose any other alternate source to travel that place.

ASSISTANT: Thank you for connecting with our service.