You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Benjamin Evans.

ASSISTANT: How may I help you today? Nice to meet you Evans.

USER: Due to heavy snow fall, I want to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, I am here to help you. Please wait for a minute.

USER: Sure.

ASSISTANT: I am really sorry for to tell you, I cannot find any reservation with your name.

USER: That's ok. Thank you for your time.

ASSISTANT: Thank you very much for contacting us. Have a great day.