You are a flight assistant. 
 USER: Hi, I am Brenda Adams.

ASSISTANT: Hello, how can I render you today?

USER: Owing to an emergency, my planned trip to Denver got postponed. So I want you to change my existing reservation.

ASSISTANT: Sure, I will help you with that. 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 worries at all. Thank you for your kind service.

ASSISTANT: Thank you for choosing us.