swampfox

Is it this one? MidwayUSA - Lee Challenger Single Stage Press Anniversary Kit with "Modern Reloading" Manual
If it is you can use the built in stuck case remover. Leave the die in the press. Loosen the decapper clamp. Put a piece of hard wood on the decapping pin and drive it out with a mallet or hammer.

Use a little penetrating oil before you hammer on it. Let it soak in for a while before doing any of this.

If you have the Lee Reloader(MidwayUSA - Lee Reloader Single Stage Press) press or you don't want to hammer on your press, remove the die. Get a 7/8-14 nut from the hardware store. Put it in a vice. Screw the die in and hammer the case out. Grab the case with a pair of vicegrips and tap it free from the decapping pin. If you are using the Lee Reloader it probably wont last long. It isn't very strong. It is more for light duty.

This is what Lee recommends: You can easily remove the case yourself, loosen but do not remove the decapper clamp with a 3/4 and 1/2 wrench. Then pound on the end of the decapper rod with a 3/16 drift punch, and use a heavy hammer for best results. You can leave the die in the press for this operation.