I did it on my HW110. It’s easy to do. I wrote instructions - I will find and post them here later. In the meantime…
Basically from memory:
remove the stock - 2 stock screws (the shorter stock screw goes towards the muzzle when reassembling)
remove the trigger guard - this requires the removal of one screw and knocking out one retaining pin
remove the rear plate (silver) - this requires lifting up the retaining spring holding the plate on - I use a dental tool
hold the mag release lever about 1/2 way up - then slide out the thin 2-pronged “pusher” that fits inside the mag release lever.
now you should be able to slide out the mag release lever and swap to the other side - then reassemble.
When reassembing, make sure that you have the two prongs fitting into the 2 “teeth” on the plate (silver again) that is the mag retention plate.
