如何用infopass reschedule FP?

請問如何用infopass reschedule finger print appointment?
是先cancel, 再make new appointment,
還是make new appointment,再cancel old appointment?
有點confused，又不敢胡亂試，請過來人指教，越詳細越好。謝謝!

還有，notice上隻有兩個reschedule選擇時間(next available
wednesday or saturday) Does that mean the following
Wed/Sat of the appointed date or any Wed/Sat in the future？

多謝。