@Olegus awful design.

I haven't broken mine yet, because I decided to Google the issue first.

This is what happens when you put form over function.

It's not intuitive, and not well designed, but fairly straight-forward.

Hold the switch itself firmly in one hand

With your other hand put your thumb on front of switch, use your other fingers on back of faceplate to bend away from the switch.  This will pop the top of the faceplate off of the switch. You have to use only moderate force.

This would be very difficult to remove from the plate once the dimmer is in place (TP-LINK - pay attention!).  I'm putting in 3 dimmers in a 3-gang, so will be using after market faceplate...

@Octechguy 

Ok , I know when I ask for instructions I would like a step by step direction instead of "if it breaks we'll replace it" answer. Here's your step by step (yes I am late to the party but I just bought these and found myself in the same position)...

***Note locate the top of the faceplate. Its marked on the back "UP" on both upper corners. 

1. Hold outlet horizontally with the front facing you and both your thumbs pressing against the outlet. 

2. With both index fingers push up the side of the back of the faceplate while firmly applying pressure downward with your thumbs on the outlet. Remember hold this horizontally. 

3. Slide your right index finger to the top of the faceplate (backside) maintaining pressure. Use 3 fingers (index, middle and ring) together to evenly apply pressure. 

4. Push up harder with your fingers snapping the faceplate off. It will sound like you're breaking the plate. 

I did this 5 times before writing this to make sure it works. Good luck to all. 

@NJBob this is a total design fail.  "Try to snap it off and we'll replace it if it breaks".  I can't get the damn face plate off the unit.

NJBob wrote

I just bought two HS220's and am ready to begin installation, however, I can't get the faceplate off and I'm afraid to force it.  What's the trick?

Thanks!

@Carl 

How do I go about getting a new wall plate? 

Mine broke when trying to take off.

i cut my hand trying to get this poorly engineered face plate off!  instead of telling customers you will replace them , how about building them correctly in the first place?

It's NOT that difficult, people!! Grab the thing and bend it. It'll snap right off. If you want it off the wall, slide a knife behind it and pull. You're more likely to break the knife than the faceplate. I happen to think it's quite a good design, personally; though it does look a bit boxy.