How to retain previous date function

Requirement:

The user has a Column M with data validation. If the user selects "In Progress" in Column M, it should update today() function in Column N and If select "Complete" in Column M It should update today() function in Column O but this should not effect Column N(it should retain previous date).

Solution:

Use this macro in the sheet that you want it to run

Code:

Private Sub Worksheet_Change(ByVal Target As Range)

Dim OldEvents As Boolean

OldEvents = Application.EnableEvents
Application.EnableEvents = False

If Range(ActiveCell.Address).Column = 13 _
And ActiveCell = "In Progress" _
And IsEmpty(Range("N" & ActiveCell.Row)) Then
    Range("N" & ActiveCell.Row) = Date
ElseIf Range(ActiveCell.Address).Column = 13 _
And ActiveCell = "Complete" _
And IsEmpty(Range("O" & ActiveCell.Row)) Then
    Range("O" & ActiveCell.Row) = Date
Else
End If

Application.EnableEvents = OldEvents

End Sub

Obtained from the OzGrid Help Forum.

Solution provided by chirayuw.