You are a flight assistant. 
 USER: Hi, I am Thomas Lopez.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no reservation with your name.

USER: Ok, no worries at all.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your kind service.