first, I'm not a professional but I'm looking at it as a 1st time home owner w/ little money. :)

Can they take the cabinet in question off the wall then using a reciprocating saw (I think that's the one they want)cut off on a premeasured line?

I can't see any other way w/o damaging the attached cabinet. It appears that that the thickness of that wood will make it too much to cut into slightly (like scoring wallboard) to wiggle the piece back and forth to cut off. Then taking a sander-smoothing the rough edges. I really wouldn't recommend that way.

I hope you can get a good and quick reply soon!

If you can't remove the cabinet from the wall, I would consider cutting the side off just below the shelf. It is a bit tricky but it can be done. I would mark a straight line using a level or square, and then place a piece of painter's tape along the top of the line (the bottom edge of the tape is where I would cut). Next I would slowly, and I mean slowly, cut the line with a jig saw (new blade of course). When you get close to the wall you will have to stop and use a hand saw(a japanese style one would work best due to its small size). If life is treating you kindly, you may be able to just sand the bottom of the cut edge, prime, and paint it. However, if you have a jagged edge, or want a more finished look, you may need to pick-up some trim to cover the edges. According to your DIY skills and tools, you could just cover the shelf with a wider trim and or you could wrap the trim across the front of the shelf, bump it out around the front column, then wrap it on around the side. I played with your pictures to give you an idea of what I mean. The first one just has the right side cut off and a trim piece on the shelf. The second picture has both sides cut off (if you can do one you should be able to do both) and a trim piece on the shelf.

BTW, if you can take them it off the wall I would still use the same tools and cutting process.

Hope this helps,
Nancy

it'll look really nice if it's done. i'd try to take it down to do it tho. maybe your sil or dd have some carpentry skills tho?

Nancy,
Thank you so much for going to all that trouble. I believe that I can tackle all the steps you described. The pictures helped - especially when it came to understanding about the trim piece on the bottom shelf.
We can't (don't want to) take down the shelf, as the wall is plaster, not drywall and we want to avoid as much damage as possible. Your solution sounds like it fits my meager DIY skills.

What Nancy said, except just use a thin blade Japanese saw for the entire job. If you aren't used to using a jigsaw it can get out of bounds with a quickness. A hand saw will be easier to view the line and easier to handle. It will just take 1 minute instead of 30 seconds. And less dust and noise. You can get that type of saw for $20 +/- at one of the bix box stores.

To make a clean cut you need a horizontal strip of wood as a guild for the saw to rest on. I could explain how this all works but you need the tools and a certain level of skill to do it right. Because this is a temporary situation I think you're best doing it by hand with a Japanese pull-saw like has been already suggested. The better the quality saw the eaiser it will be to make a straight cut. Score your cut line with a utility knife so the wood doesn't splinter. The Fien tool others have suggested will cost around 300 dollars with the baldes and is dangerous and hard to control. I'm glad to give further instructions if you need.

I meant to say guide for the saw to rest on.
Sorry.Also the guide should extend past the cabinet by at least six inches.

I just wanted to thank everyone for their time and expertise. It was so helpful. Everything went very smoothly. I would never have thought to put the trim piece on the bottom and that made all the difference.
I've included an AFTER picture. The wall was scuffed up a bit, but they hope to change the wall color soon, so there was no need to paint the scratches.
Again, thanks for taking the time to help a stranger.
{{!gwi}}

Wow! That looks great - Congratulations!