cardPresso supports duplex printing, generally speaking.
The process that leads into it could be different depending on a simple factor.
If a printer has an inbuilt flipper, the printer itself should automatically flip the card after printing the front side, then proceed with printing the back one, without any user action having to be taken.
However, in case there’s no inbuilt flipper, the card shall be ejected into a single card slot and the end-user must manually remove the card, flip it accordingly, then reinsert it in the same slot from where it was previously ejected, and the pending job shall automatically resume itself.