You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Anna Mitchell.

ASSISTANT: How can I assist you Anna?

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

ASSISTANT: Ok, please hold on for a moment till I check with your reservation.

USER: Ok.

ASSISTANT: Thank you for waiting, I appreciate your patience. I am very sad to inform you but there is no reservation under the name of Anna Mitchell.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching our services, have a great day Anna Mitchell.

USER: You are most welcome.