Encontrei muitos exemplos para alterar temas no Word 2010. Aqui está uma explicação simples:
A theme in Microsoft Word 2010 consists of colours, fonts and effects. Unlike individual styles that you can apply to each element (tables, charts, etc), a theme affects all the content in your document.
You can apply a theme with one click and the theme affects the style of the whole document, providing a consistent look and feel across all its elements. This means that the document’s tables and charts will look good together.
Source: Microsoft Word 2010 – Themes
Você pode alterar estes temas aqui:
When you apply a theme to a Word 2010 document tables, charts, SmartArt graphics, shapes, and other objects are updated to complement one another.