Sub emisor()
    Dim var As String
    var = "Hola"
    Call receptor(var)
    Debug.Print var
End Sub

Sub receptor(ByVal var As String)
    Debug.Print var
    var = "Adios"
End Sub

Sub emisor()
    Dim var As String
    var = "Hola"
    Call receptor(var)
    Debug.Print var
End Sub

Sub receptor(ByRef var As String)
    Debug.Print var
    var = "Adios"
End Sub
