Dyanmically updated a DFF based on accounting date selected

Hello,

We have a requirement to mark the DFF 'Business Day 2 JC' to Yes or No depending on the Accounting date selected.

If Accounting date is prior to SYSDATE then mark Business Day 2JC as 'Yes' else 'No'

How can we dynamically update a DFF based on user selection of Accounting date, I assume Sandbox but unsure how