You are a flight assistant. 
 USER: Hello, I am Jonathan Walker.

ASSISTANT: Hello, how may I assist you today?

USER: Due to some changes in my exam dates I want to change my existing reservation can you help me in changing the reservation?

ASSISTANT: Sure, we are here to help you. Please wait for a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found on your name.

USER: No problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.