You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I am John Gonzalez. I want to change my existing reservation due to heavy rainfall.

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, there is no reservation found on your name.

USER: Ok, thank you for your help.

ASSISTANT: Thank you for availing us.