Hi, I am an electrician and can help you with this problem.
Most switches (and plugs for that matter) that provide an option for terminating wires by inserting them in holes instead of using screws, also provide a means of releasing the wire. The device on the right in the image below shows openings to do just that:
By pressing a small / thin screwdriver tip, nail, etc.in the release opening(s) adjacent to the wire(s) - you will relieve the spring tension that holds the wire in place, and can easily pull the wire out. Not all devices provide a way to release a wire however. These devices will require either cutting the wire close to the device or a "pulling away" while "twisting back and forth" motion of the device to get the wire out. The conductor will likely be scored as a result.
Attempting to release the wire from a device should only be done with power off, as inserting a tool into the holes will place it in direct contact with energized parts.
Lastly, some words of caution. You should reconsider using this method to terminate wires on devices. A screw terminal provides a much better electrical and mechanical connection. The comparatively small contact area provided by the internal spring can quickly heat up under a load. Once heated, the spring metal loses strength and the connection worsens. Eventually it fails - hopefully before the heat causes a fire. No electrician would wire his own home with these connections, you shouldn't either. If you insist on using these connections, do not reuse them. The springs lose strength when the release opening is used to get a wire out - and loses shape (weakens) after a wire has been pressed in.
I hope this helps & good luck!