You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER:   Due to sudden change in my planned dates of journey, I would like to change my reservation. Can you please help me out with changing of my reservation?

ASSISTANT: May I know your name for further process?

USER: Thank you and my name is Robert Hernandez.

ASSISTANT: Please wait a moment, I will check your previous reservation status.

USER: Ok.

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

USER: Ok, no problem with that one. Thank you for your assistance.

ASSISTANT: Thank you for choosing us, have a nice day.