To change a 3-way switch installation to a conventional one, you need to connect one of the "travelers" to either the hot wire or the one going to the light, depending on which box this is. Then you cap (put a wirenut on) the remaining traveler. If the remaining switch turns the light on when it is down rather than up, you can either invert the switch or switch the hot/light wire to the other traveler in the now-empty box.

If none of this makes sense, you will need to either research basic 3-way switch wiring, or consult an electrician for help.

I hope you took a photo of the wiring before you removed the switch.

Something looks wrong about your picture, however. Why would a switch be located near the baseboard? Also, what was connected to the white wires?

Hello. That's not baseboard, its chair rail molding. The white and red wires were formally attached to the light switch.

Chair rail. Never thought of that. :\ Thanks.

Are you saying that there were FOUR wires connected to the switch? (Not counting a possible bare ground wire.)

Was it a conventional snap switch, or some kind of electronic device? How many screw terminals did it have? Do you have a photo of the way it was connected before you removed it?

Your not completing the circuit, I would join all the like colors together, and see if that works.

I would join all the like colors together, and see if that works.
Sorry, that's not such a great strategy where a 3-way switch is involved. Wiring requires a lot more than just matching wire colors. It's not uncommon to open a box and find a white wire and black wire connected together, especially in an older house, and it's not a mistake.
To make this work the way the OP wants, he needs to connect two wires together, and leave one wire in the box disconnected and capped with a wirenut. His problem is to determine which ones to connect and which one to cap.

I can't see inside the box as well as I'd like to, so it's possible that I'm not seeing something. Or maybe my brain has skipped a gear. But what I think I see in the photo doesn't seem to be normal wiring for a 3-way switch.

In a j-box for just a 3-way switch, I expect to see 2 cables entering the box. One will be 3 wires plus ground (red, black, white, bare) and the other will be 2 wires plus ground (black, white, bare). From the latter cable, the black wire goes to the switch common terminals. From the former one, the red and black go to the switch traveler terminals. The white wires are tied together.

That's not what I'm seeing here.

With more information from the OP maybe we can figure this out.

could it be a 4-way switch

Yeah, that's what I was wondering too. But the hots tied together still seems wrong.

It probably doesn't matter though, since the OP hasn't been back.

The simplest way is to stop using one of the switches. Electrical code dictates minimum switch locations and that may be one of them.

JM$.02W

Agree. He should never have removed the old switch. He is going to have to leave the box there in the wall and it must remain accessible. (He can not sheet rock over it!)