You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Stephanie Carter this side, I am planning to do some changes in my dates of journey in my previous reservation. Can you help me?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: First please confirm whether my reservation is existing or not.

ASSISTANT: Ok, hold on for a moment. Let me check. Sorry Carter, there are no flights reserved on your name.

USER: Take your time. Ok, Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us.

USER: You are welcome.