I applied part of my refund to the 2019 taxes, but it didn't change the amounts shown on my estimated tax coupons. It did for the State, but not for the Federal.

I assumed it would take the amount assigned to 2019 off the first couple of estimated taxes, but it didn't. Where did the money go that I assigned to 2019??? This happened last year too, and I wound up with a large refund when I first started the 2018 form. I want to reduce the estimated payments. How do I do that?