You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my reservation which is done recently due to some problems, can you please help me out?

ASSISTANT: Sure, I can help you with free of cost. May I know your name for checking your previous flight ticket booking?

USER: Thank you. Sure, my name is Kevin Clark.

ASSISTANT: Thank you for your information, no reservation has found under your name to help you in changing process.

USER: Ok, that's fine. Thank you for your service.

ASSISTANT: You are welcome and have a nice day.