You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Donald Hernandez.

ASSISTANT: How can I help you?

USER: I want to change my existing reservation, due to heavy rainfall in New York.

ASSISTANT: Ok, I will check the details on your name. Please give me a minute.

USER: Ok.

ASSISTANT: Sorry Donald, there is no reservation found on your name.

USER: That's ok, thanks for your help.

ASSISTANT: You are welcome.