You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation which is done recently due to heavy floods at Denver, can you please help me out?

ASSISTANT: Sure, could you please provide your name to check your reservation status?

USER: Sure, my name is Christopher Davis.

ASSISTANT: Ok, please hold on for a moment I will check your details and proceed further.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: Ok, no problem. Anyways, thank you for your appreciable service.

ASSISTANT: Thank you for reaching us, have a nice day.