Sub travdemande()
Dim nomfeuille1 As String
Dim cellule As Range
nomfeuille1 = ActiveSheet.Name
With Sheets(nomfeuille1)
For Each cellule In .Range("a2:a" & .Range("a65536").End(xlUp).Row)
If IsDate(cellule.Value) Then
.Range("e" & cellule.Row) = "1/1/" & Year(cellule.Value)
Else
.Range("e" & cellule.Row) = "1/1/" & cellule.Value
End If
Next cellule
End With
End Sub