You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Matthew Miller. Due to deal with an important case, I have to change my previous flight ticket booking. Can you please help me in flight ticket changing?

ASSISTANT: Sure, I'll help you in changing an existing reservation. Please wait a moment I will check the reservation status.

USER: Thank you for accepting my request and I can wait for your response.

ASSISTANT: Ok, please wait a moment. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Ok, no issues with that one. Thank you for your quick information.

ASSISTANT: Thank you for approaching us.