When you work on a document that is stored in a workspace, you can block authors from changing specific sections.
The Block Authors feature is available only when your document is saved in .docx format to a Windows Live SkyDrive or Microsoft SharePoint Foundation 2010 site that supports Workspaces. You can save to any Windows Live SkyDrive or to a server that has Microsoft Office SharePoint Server 2007 or Microsoft SharePoint Server 2010. To work with SharePoint in Office for Mac, you have to have Microsoft Office for Mac Home and Business 2011, Microsoft Office for Mac Academic 2011, or Microsoft Office for Mac Standard 2011.
Select the part of the document that you are working on.
On the Review tab, under Protection, click Block Authors.
The section is now marked as blocked.
Tip To remove a block, click in the blocked section, and then on the Review tab, click Block Authors or press ⌘, click the blocked area, and then click Block Authors.