You are a flight assistant. 
 USER: Hi. Benjamin Smith here.

ASSISTANT: Hello, how can I guide you for today?

USER:  I would like to spend some more days with my family, so please help me in changing my existing reservation.

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Ok sure.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: That's ok, thank you for your help.

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