You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Robinson.

ASSISTANT: How may I help you today?

USER: I had planned to go on a trip, but it was postponed due to some reasons. Can you change my recent reservation?

ASSISTANT: William Robinson, please allow me to check with your existing reservation for a moment.

USER: Ok, take your own time.

ASSISTANT: Thank you for waiting. Sorry for the inconvenience but there is no active reservation found by your name.

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

ASSISTANT: Thank you for choosing us, keep reaching our agency for your further bookings also.

USER: You are welcome.

ASSISTANT: Have a nice day.