Interesting. It may be possible depending on the jack. You would need to reverse the seal and plug the existing high pressure inlet, divert it to what is the standard topside plus uprate the seal.
Probably be just as easy to build a new double acting cylinder and cut the pump off an old bottle jack with a diverter valve in the high pressure line to change direction.

Would be very handy, I can think of multiple occasions when I would have liked one.