You are a flight assistant. 
 USER: Hello. I am Donna Rodriguez.

ASSISTANT:  Hello, How exactly I can serve you the best today?

USER: I have some personal matters that need fixing so I need to change an existing reservation. Can you please help me to change an existing reservation?

ASSISTANT: Sure, I will help you with that.

USER: Sure.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for approaching us.