Changing the font of the Normal style is as simple as:
Code:
Function ChangeFont(oDoc As Document) As Boolean
Dim oStory As Range
On Error GoTo err_Handler
oDoc.Styles(wdStyleNormal).Font.Name = "Calibri"
ChangeFont = True
lbl_Exit:
Exit Function
err_Handler:
ChangeFont = False
Resume lbl_Exit
End Function
However, changing the Normal style in this way means it will no longer be the same as the document defaults which may lead to Table Styles not working correctly. It is not possible to set the document defaults using VBA.