You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kevin Lopez.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation due to bad weather condition, can you help me in change reservation?

ASSISTANT: Sure, I can help you with that. Please wait for a while.

USER: Sure.

ASSISTANT: Kevin, there is no reservation found under your name to do changes in that.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.