You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I render you today?

USER: Can you please help me in changing my reservation with name Dennis Baker?

ASSISTANT: Sure, I will help you with that. Please wait a while.

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 issues. Thanks for your service.

ASSISTANT: Thank you for choosing us.