I tried to the following way : But it didnot work ( means font remained unchanged)

Code:
 void EmfCellListRend::DrawRectangle(EmfCellListRendDrawingParams* pParams, TDC& dc, CEmfCellList *pCelllist)
 {
	ILogicalLayerManager&	rLogLayManager  = DataManager::GetInstance().GetLogicalLayer();

	CDC* pDC = CDC::FromHandle(dc.GetHDC());

	CFont* pCurrent = pDC->GetCurrentFont();

	LOGFONT lf;

	pCurrent->GetLogFont(&lf) ;

	lf.lfWeight = FW_EXTRABOLD;
	lf.lfHeight /= 10; // make the font larger by 4
Not sure the blue coloured line is correct ? (Eventhough it compiles , but the font size is not reduced)