Have you tried removing the solder on the back of the board. If you get it all they should pull up.

Otherwise pry the plastic up with a thin screwdriver. Start at one end. And wiggle it up. If you are replacing the plastic and pins. Cut the pins off close to the plastic, less pin for the plastic to go up then.

LTG : )

I've had good luck with first re-solder, then de-solder, and then use a hot air rework station to heat the pins, and when the remaining solder is hot enough, they pull out cleanly all in one (the whole connector group). This has worked the best for me, rather than try to remove the white part, or cutting the white part so you can remove each pin individually.

Without hot air, my second string attach would be, carefully cutting the plastic into seperate pins, and re-solder, then heat the solder while pulling out the pin, then de-solder.

It can be tough to remove without a desoldering station if there is a lot of solder balled up on the back side of those headers under the plastic.

Using a brand new blade in your razor knife, slit the plastic lengthwise along the pins, in one long cut. Don't get too excited, cut about halfway through.

Now flex the resulting plastic tab slightly, while you make a second finishing lengthwise pass

Wiggle the other half still attached to the pins and it will come right off.

Use flux, add a bit of new solder, and turn up the solder station heat. Move quickly as to not lift pads...

Flux is your friend on old, oxidized solder

Cut the pins flush with the connector. Pry off the plastic piece; I’ve always done this without heat, but you may have to use a little. Once the plastic is off, removing the remaining pin pieces and solder is relatively easy.

These WMS boards have massive and thick ground fills that act like a heat sink. If you are having trouble getting the solder to flow may need more heat. Certain points I would double fist using a wand and the desolder gun at the same time to get the solder to melt on these large areas. Adding new solder(and/or flux) helps too if the old stuff is scummy.

I simply put a lot of heat on a pin, put pressure on it, when it moves a bit, I pull on the pin from the component side, pulling it through the melted solder and partly melted plastic. Once they are all out, the plastic might be a little stuck by the pulled solder from the pins but can easily be pryed off. Then just cleaning the pads finishes the job. I never try to remove the whole connector at once, too time consuming.