Can a one way lamp swtich be converted to a 3 way switch?
If you look inside the lamp-socket for a three-way lamp, you'll see three contacts, rather than two. Replace the existing two-contact light socket with a three-way socket and switch.

However, there are few three-way "bulbs" available, and very few energy-efficient LED or CFL three-way bulbs (which are a bit pricey), you'd be better off using a small dimmer switch in the base of the lamp, or using a remote controlled LED bulb.

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