How to reset the new magic (2) keyboard

Hi, I have the new apple apple keyboard that I use at work via a USB/bluetooth dongle.

I have had to move computers at work and the keyboard works on the new PC via the USB charging cable, but no longer via the Bluetooth dongle.

I believe I unpaired the keyboard from the old PC (but might have just have deleted the Bluetooth dongle).

I have searched the internet high and low, but all comments I've found are concerning the older style that has the power button and replaceable batteries. Is there a way to reset the new keyboard? Some kind of key combination or something?