Populate a cell using a formulae without adding the formulae to the cell you populate

I don't know enough about formulae to know if this is possible. What I want to do is populate a cell based on a checkbox in another column being selected but without adding a formulae to the cell I want to populate (so adding the formulae somewhere else). The reason is that any cells that are not populated will have a dropdown and users will be assigned manually. When the project is over I would like to reuse the sheet so i don't want to have to go back in and add all the formulae to the cells that were manually changed.

The first part is easy:

=IF([Include in update]62 = "TRUE", "N/A")

I put this formuale into the 'Person assigned' column and when the box is checked it writes 'N/A'. I want N/A to be written to this column when the box is checked but I want to do this by writing the formulae in another hidden cell. Is that actually possible? If not is there another way to reset a sheet to its original state without having a copy (bearing in mind that most of the rows are populated with text at the start of the project).