My appologies, 12/30/39 is a Saturday, I must have entered 1940
originally, also my bad, for the formula provided is a worksheet
formula, not a VBA code.
Here it is again with the proper weekday

=DATE(YEAR(E1),MONTH(E1),DAY(E1)+CHOOSE(WEEKDAY(E1 ),-1,-2,-3,3,2,1,0))


If you wanted a VBA code to Change E1 to the nearest Saturday, then
perhaps a helper cell would work.

Sub NearestSat()
Dim h As Range
Set h = Range("H1")
h.Value = "=DATE(YEAR(E1),MONTH(E1),DAY(E1)+CHOOSE(WEEKD AY
(E1),-1,-2,-3,3,2,1,0))"
Range("E1") = Range("H1").Value
h.ClearContents
End Sub