How to Override the Master Text Style in PowerPoint 2007
The PowerPoint Slide Master specifies a text style but you can format your PowerPoint slide’s text while you’re working in Normal View. The formatting changes you make apply only to the selected text. The Slide Masters aren’t affected.
If you change the layout or formatting of text elements on a slide (for example, if you move the title placeholder or change the title font) and then decide that you liked it better the way it was, you can quickly reapply the text style from the Slide Master.
Right-click the slide in the Slide Preview pane (on the left side of the screen).
Choose Reset Slide from the menu that appears.