Sub Test()
Dim t$, plage1 As Range, plage2 As Range
Dim Service As Range, HDébut As Range, HFin As Range
t = UserForm1.Label4
If t = "" Then Exit Sub
Set plage1 = ActiveWorkbook.Sheets("Bases").Range("A1:A12")
Set plage2 = ActiveSheet.Range("N3:AY3")
Set Service = plage1.Find(t, , xlFormulas, xlWhole)
If Service Is Nothing Then Exit Sub
t = Service(, 5).Text
If IsDate(t) Then
Set HDébut = plage2.Find(CDate(t))
If Not HDébut Is Nothing Then MsgBox "HDébut " & CDate(HDébut) & " en " & HDébut.Address
End If
t = Service(, 6).Text
If IsDate(t) Then
Set HFin = plage2.Find(CDate(t))
If Not HFin Is Nothing Then MsgBox "HFin " & CDate(HFin) & " en " & HFin.Address
End If
End Sub