When you check out the current working version of a document, it becomes unavailable to other users. They can still view the document, but they cannot make any changes until you check the document back in.
To check out a document:
In the application view, click the Documents tab.
In the table pane, select the document you want to check out.
Click .
In the File Check Out dialog box, select whether you want to copy the document from Collaboration to your computer or use the document on your hard drive. If you do not download the current version of the document, you might be overwriting someone else's changes.
Click Finish.
If you have downloaded the current version, in the File Download dialog box click Save.
If you have downloaded the current version, in the Save As dialog box select the location where you would like to check the document out to and click Save.