Royal Empress

The brown part looks a bit dead to me. So I would cut it back to the leaf joint just below the dead part. Sadly this will mean that it will not grow into the 70 foot tall tree which is what it is supposed to do. What you will get, if you are lucky is suckers coming from the roots and buds developing from below the cut. These will make nice side branches which will have huge elephants ears size leaves.

I agree with the above.
They are certainly hardy in the uk but I dont know how cold Missouri gets. if the worst of your winter is over pop it out side during the day, bringing it in at night for about 2 weeks then plant it outside.

It can still grow to full size, Rachm. After you cut it, it will produce several branches. When they have 2-3 pairs of leaves, choose the strongest one, and tie it to a stake to straighten it--gently!--and pinch the growing tips out of the others. The one you staked will form the new leader, and the others can be removed this coming winter. Be sure to keep it chilly until it is time to plant it this spring. If it sprouts prematurely, it will need to be hardened off before you plant it.

In all the years I have been growing things I have never managed to do the above. I have seen that advice given many time before though. I wonder if anyone has actually ever achieved it?

It's a common gardening technique, Owdboggy. What happened when you tried it?

The new leader grew all right, but it always had a 'kink' in the stem and the tree had a peculiar shape where the dead leader had died. In the end I pollarded it and turned it into a multi-stemmed shrub. This was an Acer by the way.

Well, the kink will gradually become less conspicuous as the trunk thickens. The time frame for this depends on the growth rate of the tree, and how well and early the new leader was staked

10 years on and the 'kink' was still visible and it was staked the day after the leader snapped.
Love to see actual photos of this being done over the time scale though.
Not saying it is not possible, just never managed it myself. Probably my cackhandedness.

Thank you so much for all of your comments! I had a busy work week this week and was not able to plant her outside yet, and today, the first day of spring, we wake up with an inch of snow on the ground! LOL It is a very wet snow and is supposed to be in the upper 40's later today so it will be gone by this evening, but still. Grrrr! (I am in Missouri, St. Louis area. We are used to this.) It was 81 degrees on Monday and Tuesday this past week.

Well, 10 years is small change for an Acer, Owdboggy, if you're talking about A. palmatum. If you want to see the results with faster growing trees, look at any grafted fruit or nut tree.
I sympathize with you, Rachm. It's been ups and downs here too, though our ups are upper, and our downs are not so down. My Brazilian rain tree bonsai at work doesn't know what to do.