Tools for Lacerte:

(1) Go to Forms view and find the form you want (maybe check the Show All box in the left. Find the line or box you want and RIGHT CLICK then select "Jump to Input" 

(2) In Detail view use Ctrl + F to start a search > Find an Input Field and use "sick leave" 

All roads lead to Screen 38.4 IF you are asking about Individual return.

Welcome to Lacerte, and always remember that zero is a Negative One (-1)

How do I make the election to use prior year earnings?

Toward the bottom of Screen 38.4  Other Information

Nothing there to make the election. The only thing that works is to override the Prior year net earnings from self-employment.