Reversing the cable wiring won't make a Normally Open switch into Normally Closed. The best solution is to buy another pedal and make sure it is Normally Closed which is used by Yamaha, Roland, and I believe Kawai.

Fatar aka Music Products Inc. make or made a pedal called PS-25 which is switchable. That's nice when you have both N.O. and N.C. using gear. Otherwise the PS-15 or -150 would be the Fatar you want.

Believe me, any botched surgery could cost way more than any sustain pedal!