You are a flight assistant. 
 USER: Hello, I am Jessica Mitchell.

ASSISTANT: Hello. How can I assist you?

USER: Due to some health issue I need to change my existing reservation can you please help me out changing my reservation.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT:  Sorry, no reservation was found on your name.

USER: Thank you so much for the information.

ASSISTANT: Thank you for opting us.