It is easy to remove lenses from reading glasses. You can use press your thumb on the lenses, the lenses will pop out. If the frame hold the lenses tightly and it can't pop out when you press the lenses, you can use a tiny screwdriver to lose the screws of the front frame, then, you can take out the lenses easily.
To remove the lenses out of your eyeglasses frame, you are suggested to prepare a tiny screwdriver first. Then, put the eyeglasses on a desk and use your screwdriver to lose the screws. Please keep your screws well. Then, you can remove the lenses easily. After you taken out of the lenses, put on the screws and tighten it with your screwdriver. If you still have no idea how to do it, you'd better have an optician to remove it for you.