Sub CATMain()

Dim partDocument1 As PartDocument
Set partDocument1 = CATIA.ActiveDocument

Dim selection1 As selection
Set selection1 = partDocument1.selection

selection1.Search "(Name='länge.1' & CATKnowledgeSearch.InternalParameter),all"

Dim part1 As Part
Set part1 = partDocument1.Part

Dim parameters1 As Parameters
Set parameters1 = part1.Parameters

Dim length1 As Length
Set length1 = parameters1.Item("Part3\Länge.1")

Dim bSTR1 As String
bSTR1 = length1.Comment

length1.Rename "L.1"

bSTR1 = "L.1"
part1.Update

End Sub