I'm very confused. What do you mean retired? Are you sure the switch in the hall controls the office receptacle?
It's a three-way (not three-pole) switch. There should be another switch somewhere that also controls the hall light (typically at the far end of the hall or perhaps if there is a run of stairs, at the bottom of the stairs).

The second hall light switch is a convenience which you could remove. If the second switch is at the other end of a stairway, this is a SAFETY issue (not electrical but building safety for requiring stairs to be lit). You should not be removing the second switch in that situation.

There's not currently enough information in your post to answer this fully, but yes typically, you can disable the second switch and put a single-way switch in. How to do that depends on how things are wired. Of course, the easiest way would just be to replace it with another three way.

If the hall switch really controls a receptacle in the office, removing that from the switch is less likely to be done at the switch end but again not enough information here.

That should say "rewired" not "retired" lol. Autocorrect...

Anyway, yes, the switch for some reason runs that receptacle because it turns off the answering machine and shredder. No other switch controls the light in the hall other than the one in question. The switch in the office runs one of the outlets in the office double receptacle but not both, but the hall switch runs both of the receptacles in the office. The hall is very short - just off of the garage, so it wouldn't really need a second switch to run it.

I could replace the hall switch with another three way, but then I would have to always have the hall light on so that the office phone would always be on. I suppose the easy way out would be to just plug the answering machine/phone into a different outlet, but the phone jack is located near the problematic outlet, so I'd have to get a long extension cord to run to a non-problematic outlet.

The weirdest thing is how that hall light never ran the office outlet until we unwired and rewired the switch. We kept wondering why it was a three way switch if it only ran the light. It is so confusing!

Well, it's possible that someone butchered the wiring previously.

The other option is you screwed up your rewiring job. Are you sure you put it back EXACTLY the way it was before. It's possible you that the wire was connected to the power feed at the switch and you moved to to the switched side. Did the old switch actually have three SCREWS on it (other than ground) or was one wire inserted in one of the "backstab" holes (or perhaps two wires under one screw).

Now that you mention it, two wires were backstabbed and one was on a screw. It is possible that I reversed the two backstabbed ones. The screw one is unchanged because it was already in a wrapped shape, so I knew it went on the screw. Is there any issue with trying to switched the backstabbed wires to see if the problem goes away? Any chance one of the backstabbed ones wasn't inserted all the way to begin with & so wasn't making the connection to run the back room originally?

And now we have noticed that the switch runs ALL of the outlets in the office. This is fun. I think I might just have an electrician look at it... He/she will probably roll their eyes at the simplicity of the solution...lol

The switch was being used as a feed-through for the outlet in the office. When you put it back in, you connected the feed for the office outlet to the load side of the switch instead of the line side.

I went back and switched the backstabs and everything went back to normal. Since the replacement switch doesn't have the same exact configuration (with 2 backstabs and one screw) I gave up and decided that a cream light switch isn't such a bad thing. Thanks for the input ronnatalie and fa f3 20 - even though I was defeated by the switch in the end. Lol...