XL 2016 nom de chaque onglet selon contenu cellules dans un autre onglet

Sub renomme()
    Application.ScreenUpdating = False
    For L = 2 To Range("A65500").End(xlUp).Row
        NomAvant = Cells(L, "A"): NomAprès = Cells(L, "B")
        If FeuilleExiste(NomAvant) = True And FeuilleExiste(NomAprès) = False Then
            Sheets(NomAvant).Name = NomAprès
        End If
    Next L
End Sub
Function FeuilleExiste(Nom) As Boolean
  On Error Resume Next
  FeuilleExiste = Sheets(Nom).Name <> ""
  On Error GoTo 0
End Function

Sub Nommer_onglets()
Dim s As Object
On Error Resume Next
For Each s In Sheets
    s.Name = Application.VLookup(s.CodeName, Columns("A:B"), 2, 0)
Next
End Sub

Sub Nommer_onglets()
Dim s As Object
On Error Resume Next
For Each s In Sheets
    s.Name = Application.VLookup(s.Index, Columns("A:B"), 2, 0)
Next
End Sub