Pre-defined Folder in Save Dialog

The following code opens a dialog for the user to choose a folder to save the file as PDF.
I'd like to set a pre-defined folder to start.
Any ideas?

Dim v As Variant
v = Application.GetSaveAsFilename(Sheets("A").Range("B6").Text & ".pdf", "PDF Files (*.pdf), *.pdf")
If VarType(v) = vbString Then
  Sheets("A").ExportAsFixedFormat Type:=xlTypePDF, Filename:=v, _
    Quality:=xlQualityStandard, IncludeDocProperties:=True, _
    IgnorePrintAreas:=False, From:=1, To:=3, OpenAfterPublish:=True
End If