You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you from my side?

USER: I want to change my existing reservation due to postponement of my meeting. So, can you please help me out with that?

ASSISTANT: I am here to help you in changing your reservation. Could you please provide your name to check the reservation status with your name in our booking list?

USER: Ok, thank you for accepting my request. Meanwhile I have reserved my flight ticket with name Jonathan Anderson please check with that name.

ASSISTANT: Can I put your conversation on hold for sometime to check the booking list? I apologise to say this Jonathan Anderson, after checking our booking list I am not able to find active reservation with your name.

USER: Ok, I will wait for your reply. Take your own time.

ASSISTANT: I am not able change your reservation as I am not able to find active reservation.

USER: Ok, fine thank you for your information.

ASSISTANT: You are welcome, thank you for reaching us.