The first question I will ask is why you want to lower the amount of lather? Most people love a lot of lather.
To your particular question, you could lower the amount of the particular ingredient that is causing the lather.
Just change the percentages of each ingredient on your
soap calculator and see what the difference it makes in your lather number. However you won't know for sure until you make the new recipe and try the soap.
Are you using any additives that are not part of a
soap calculator list? Like sugar or sodium lactate. Personally I would not change anything but that is my opinion. Good luck
Edit: 36 is a great in between number for lather but remember that when you adjust one ingredient, you may get a number for another trait that you don't want.