In LotusScript there is a class named "NotesName" to do such manipulations.
If there is a field named "NAME" in you document, then the code would look like:
Dim doc as NotesDocument
Dim nnName as NotesName
'Somehow get the document, using ws.CurrentDocument.document
'or db.UnprocessedDocments.GetFirstDocument, depends on your situation
Set nnName = New NotesName( doc.GetItemValue("NAME")(0) )
Whatyourlookingfor = nnName.Common
If NAME is a Multivalue then you would have to write a loop to get the common- name for every element in the array doc.GetItemValue("NAME")
The next time you have a question, check out the language cross reference in the help... There it tells you, what the LotusScript- Pendant for @Name is.