You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Ronald Davis.

ASSISTANT: Davis, how can I assist you today?

USER: Due to some personal issues, I would like to change my existing reservation. Can you help me?

ASSISTANT: I am here to help you in changing your reservation. Let me check your reservation status in our database.

USER: Sure, take your time.

ASSISTANT: Ronald, I have not found any reservation by your name.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for contacting us and have a nice day.