You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: Myself Donna Hernandez. I want to change my previous travelling dates. Can you please help me out in changing my existing reservation?

ASSISTANT: Sure. I will help you with that. Please wait a moment, I will check your previous reservation status.

USER: Thank you for accepting my request.

ASSISTANT: There is no previous reservation available under your name.

USER: Not a problem, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.

USER: Thank you for searching.