MACRO TO SAVE AS PDF IN WORD 2010

Graham's macro doesn't display a dialog; it just saves the document with its current path and document name but in PDF format. It does what you described in your original post.

With your additional description of what you want to do, the code you need is only this:

    With Dialogs(wdDialogFileSaveAs)
        .Format = wdFormatPDF
        .Show
    End With

You can put this in a macro with some otherwise unused name, such as Sub SaveAsPDF(), and create a button on the Quick Access Toolbar or in a custom ribbon group to run it.

Is this not re-inventing the wheel? File > SaveAs > PDF will do the job without a macro.
However if you insist -

Dim strName As String
ActiveDocument.Save
strName = Left(ActiveDocument.FullName, Len(ActiveDocument.FullName) - 4)
strName = strName & "pdf"
ActiveDocument.ExportAsFixedFormat OutputFileName:=strName, _
                                   ExportFormat:=wdExportFormatPDF, OpenAfterExport:=False, OptimizeFor:= _
                                   wdExportOptimizeForPrint, Range:=wdExportAllDocument, From:=1, to:=99, _
                                   Item:=wdExportDocumentContent, IncludeDocProps:=True, KeepIRM:=True, _
                                   CreateBookmarks:=wdExportCreateNoBookmarks, DocStructureTags:=True, _
                                   BitmapMissingFonts:=True, UseISO19005_1:=True

will do the job - http://www.gmayor.com/installing_macro.htm