You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I am Charles Gonzalez. Can you please change my existing reservation? Because, my board meeting was delayed.

ASSISTANT: OK. Sure, I will help you.

USER: Ok.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Thanks for your time.

USER: Ok.

ASSISTANT: We didn't found any reservation by this name.

USER: Ok, no issues. Thanks for your time.

ASSISTANT: Thank you for choosing us.