For a specific answer, we might need some more details. Is a user
entering a date on a form that needs to be verified at that time? Is
the due date being calculated based on a different date?

It won't be too hard to do though. You can use the Weekday() function
and the DateAdd() function. Post a few more details and we'll help ya
out.

You can use logic like this:

if Weekday([duedate]) = 7 then
[duedate] = DateAdd("d", -1, [duedate]
elseif Weekday([duedate]) = 1 then
[duedate] = DateAdd("d", -2, [duedate]
end if