You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you for the day?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: Sure, myself Jessica Parker.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Welcome.

ASSISTANT: There is no reservation found under your name in our database to change.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us, have a great day.