You are a flight assistant. 
 USER: Hello, I am Richard Carter.

ASSISTANT: Hello. How may I assist you?

USER: I would like to modify my existing reservation. Due to cancel of my seminar. Could you please help me?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time, there is no reservation found under your name to change it.

USER: No worries, thank you for the information.

ASSISTANT: Welcome.