This picture looks oddly stretched here

Yes, columns too. Do you think I can reduce them to make flush with wall?

The arch itself is very nice. I like it. I also suspect those columns are load bearing.

You need to hire a contractor to complete the work for you. You're taking a big risk doing it yourself for various reasons.

Agree with removing arch and squaring those sides. Modern and clean.

If there are other arches in your home removing just the one will look odd, so keep that in mind. Also, it's highly possible it's a load bearing wall so you will need a professional to check that for you. But I'm all for squaring the arch and making it more modern.

Your dining room looks rather traditional, is the rest of your home similar? I think the arch & column is fine if that’s the case. I don’t see the point of making it look “ more modern “ if not. Unless you’re going more modern throughout ....

If you look up how to frame an arch, then you will see the header is typically above the arch. Therefore removing the arch is likely a "simple" matter of demolishing the pieces making up the arch and then drywalling, texture, prime, paint, trim. If you want to remove the columns, then you're dealing with a floor patch, too. Not so simple.

My first thought was the same as K Laurence, unless you are drastically changing the style of your DR furniture, I'd leave it alone. Spend the $$$ on a new chandelier and window coverings! Maybe an area rug....

Thank you for all the comments. I have purchased this house, not my favorite house but what was available -- very thin inventory here -- and I am going to make some changes before I move in.

I want to make the house less 1990s style by squaring the opening, painting it a pale gray-blue color and definitely changing all those window coverings.

Live there for a year before making structural changes or drastic style changes. It's very likely that the arched entry and columns are part and parcel of the whole design for the house. Removing them is not likely to remove most of the 1990's style. New paint, window coverings and of course your own furnishings will make a huge difference. When you are ready in a year, hire an architect for a consultation and walk through about changing the house style.

I am almost sure those "columns" are a decorative applique over a standard drywall and stud wall underneath.

There are two arches in the entire house -- which is weird. This opening here and another one adjacent to the stairway...so basically, the only arches are in the living/dining room space. Even the opening from the dining room to the kitchen is square.

I would probably square it off from the corners instead of raise it, if the corners are a normal door height.

Removing the arch and columns is not going to erase the 1990s. It seems like a waste of money to me. Spend your cash on doing things you love instead of trying to erase the era of the house. If the columns were heavily fluted and faux marble painted it would make more sense to change them. They don't bother me as is.

I don't like this idea. It looks fine.