Not possible with CF, which can only change formatting, or without a formula in
the "blank" cell.

Formula in B1 =A1 formatted to dddd

Or, of course, through VBA event code.

Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo ws_exit:
Application.EnableEvents = False
If Not Intersect(Target, Me.Range("A1:A10")) Is Nothing Then
With Target
If .Value < "" Then
.Offset(0, 1).Value = Format(.Value, "dddd")
End If
End With
End If
ws_exit:
Application.EnableEvents = True
End Sub


Gord Dibben MS Excel MVP

On Wed, 9 Jan 2008 11:23:39 -0800 (PST), wrote:

I'm using Excel 2003. I'm trying to use conditional formatting to have
a blank cell change to the day of the week when a date is entered into
another cell.